Year 4 Times Tables: worked examples and questions with answers
By the end of this chapter you will be able to
- Explain multiplication with equal groups, arrays and number lines, and use the fact that 3 × 4 = 4 × 3
- Multiply by 0 and by 1, and divide by 1
- Recall every multiplication and division fact up to 12 × 12, using a trick for each table
- Use inverse (opposite) facts to divide, write fact families and find missing numbers
- Find factor pairs of a number and multiply three numbers in any order
- Use a known fact to work out new facts, like 6 × 7 → 60 × 7 and 420 ÷ 7
- Solve word problems with multiplication and division, and answer quick-fire questions at speed
You should already know
- The 2, 3, 4, 5, 8 and 10 times tables from Year 3
- Counting in steps of 2, 3, 4, 5, 8 and 10
- Adding equal groups (repeated addition)
- Place value in numbers up to 10,000 (Chapter 1)
Where this leads
- Multiplying and dividing larger numbers (Chapter 4)
- Fractions of amounts (Chapter 5)
- Money and decimals (Chapter 6)
- Perimeter and area of rectangles (Chapter 7)
- The Year 4 multiplication tables check
- Multiples, factors, primes and squares in Year 5
National Curriculum for England, Key Stage 2 mathematics, Year 4. Content: Recall multiplication and division facts for multiplication tables up to 12 × 12, Use place value, known and derived facts to multiply and divide mentally, including multiplying by 0 and 1, dividing by 1, and multiplying together three numbers, Recognise and use factor pairs and commutativity in mental calculations, Practise for the Year 4 multiplication tables check (timed, quick-fire practice).
- 3.1 Equal groups, arrays and swapping the order: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.2 The 2, 4, 8, 5 and 10 times tables: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.3 The 3, 6, 9 and 12 times tables: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.4 The 7 and 11 times tables, square numbers and the whole grid: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.5 Division facts, fact families and missing numbers: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.6 Factor pairs and multiplying three numbers: Worksheet (PDF) · Answers (PDF) · lesson page
- 3.7 Using known facts, word problems and the times table check: Worksheet (PDF) · Answers (PDF) · lesson page
- Check-up and SATs-style questions: Worksheet (PDF) · Answers (PDF) · lesson page
Exercise P Do you remember?
Non-calculatorMethod. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 6 = 60
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 6 = 30
Check. Check by dividing: 30 ÷ 5 = 6. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Use the 3 times table. Count up in 3s until you reach 24.
- Turn the division into a missing multiplication. 24 ÷ 3 asks: what do we multiply 3 by to get 24?24 ÷ 3 = ? means ? × 3 = 24
- Count up in 3s until you reach 24. Each number you say is one more group of 3.3, 6, 9, 12, 15, 18, 21, 24
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 3 = 24
- Write the answer. 24 ÷ 3 = 8
Check. Multiply back: 8 × 3 = 24. ✓
Watch out. Know your 3 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 4, makes 32.? × 4 = 32
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 32 by 4.32 ÷ 4 = 8
- Write the missing number. 8 × 4 = 32
Check. Put it back: 8 × 4 = 32. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?3 to 6: 6 − 3 = 3. We are counting in 3s.
- Fill each gap. Add 3 to the number before the gap.6 + 3 = 9
12 + 3 = 15 - Say the whole sequence. Read it from the start to check it sounds right.3, 6, 9, 12, 15, 18
Check. Every number is a multiple of 3: 3, 6, 9, 12, 15, 18. ✓
Watch out. Check each jump is the same size (3), including the jump into and out of each gap.
Method. There are 5 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 5 equal bars show 5 equal groups. Each bar is 8. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.5 × 8
- Work it out. Use a times table trick.10 × 8 = 80
half of 80 = 40
5 × 8 = 40 - Write the answer. Include the unit.40 apples
Check. Divide back: 40 ÷ 5 = 8. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Equal groups, arrays and swapping the order
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
Multiplication is a quick way to add equal groups. Imagine 3 bags with 4 apples in each bag. You could add 4 + 4 + 4 = 12. It is quicker to write 3 × 4 = 12. We read it as “3 groups of 4”, “3 lots of 4” or “3 times 4”. The first number is how many groups. The second number is how many are in each group.
An array puts the objects in neat rows (across) and columns (down). This array has 3 rows with 4 dots in each row. It shows 3 × 4 = 12. Now turn the array on its side. There are 4 rows with 3 dots in each row. That is 4 × 3 = 12. It is the same number of dots! So 3 × 4 = 4 × 3. This is called commutativity: you can multiply in either order and get the same answer. It means that you only need to learn half of the facts.
You can also count in steps on a number line. Each hop is the same size. Six hops of 4 take you to 24, so 6 × 4 = 24. Counting in steps is called skip counting.
Two special numbers. Multiplying by 1 means 1 group, or groups of 1. 1 group of 7 is 7, and 7 groups of 1 is 7. So 7 × 1 = 7. Multiplying by 1 does not change a number. Multiplying by 0 means no groups, or groups with nothing in them. 5 plates with 0 biscuits on each plate is 0 biscuits. So 5 × 0 = 0 and 0 × 5 = 0. Anything times 0 is 0.
Key words. A product is the answer to a multiplication. The numbers you multiply are called factors. A multiple of a number is in its times table. The inverse of multiplying is dividing, and you will meet it in Section 3.5.
Key ideas
- Multiplication means adding equal groups: 3 × 4 = 4 + 4 + 4 = 12.
- An array has rows and columns. r rows with c dots in each row is r × c.
- Multiplication can be done in either order: 3 × 4 = 4 × 3. (This is called commutativity.)
- Any number × 1 is that same number.
- Any number × 0 is 0.
Key words. Multiplication is a quick way to add equal groups. A group is a set of things together.
Method. Count the groups and how many are in each group. All the groups are equal, so you can add them up or multiply.
- Count the groups. Each plate is one group.There are 4 plates.
- Count how many are in each group. The groups are equal, so count in one group only.Each plate has 6 biscuits.
- Write it as an addition. Equal groups can be added.6 + 6 + 6 + 6 = 24
- Write it as a multiplication. 4 groups of 6 is 4 × 6.4 × 6 = 24
Check. Count in 6s: 6, 12, 18, 24. The last number is 24. ✓
Watch out. The first number says how many groups. The second number says how many in each group.
Key words. An array is dots or objects in rows and columns. Rows go across and columns go down.
Method. Count the rows and the columns. An array with r rows and c dots in each row has r × c dots.
- Count the rows. Rows go across.There are 5 rows.
- Count the columns. Columns go down. Each row has the same number of dots.There are 7 columns.
- Write the multiplication. 5 rows of 7 is 5 × 7. Count in 7s, 5 times.7, 14, 21, 28, 35
5 × 7 = 35 - Turn the array on its side. Now there are 7 rows of 5. The total is the same.7 × 5 = 35
Check. Count in 5s instead: 5, 10, 15, 20, 25, 30, 35. ✓
Watch out. The total is the same both ways round, but the sentence is different. 3 rows of 4 is 3 × 4.
Key words. Commutative means you can swap the order and the answer stays the same.
Method. Multiplication can be done in either order, so 9 × 4 has the same answer as 4 × 9.
- Write down the fact Mei knows. 4 × 9 = 36
- Swap the numbers round. 4 groups of 9 and 9 groups of 4 have the same total. You can see this by turning an array on its side.9 × 4 = 4 × 9
- Write the answer. 9 × 4 = 36
Check. Count in 9s four times: 9, 18, 27, 36. ✓
Watch out. Swapping the order works for multiplication. It does not work for subtraction or division.
Method. Multiplying by 1 leaves the number the same.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 1 = 1 × 7. Use the 1 times table trick.7 × 1 = 1 × 7
- Say what the multiplication means. 1 group of 7 is just 7.1 group of 7 = 7
- Write the answer. 7 × 1 = 7
Check. 7 groups of 1, or 1 groups of 7: both are 7. ✓
Watch out. Multiplying by 1 does not change the number. It does not make it 0 or 1.
Method. Zero groups, or groups with nothing in them, always make 0 in total.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 0 = 0 × 9. Use the 0 times table trick.9 × 0 = 0 × 9
- Say what the multiplication means. 0 × 9 means 0 groups of 9. There are no groups, so there is nothing.0 groups of 9 = 0
- Write the answer. Anything multiplied by 0 is 0.9 × 0 = 0
Check. Adding groups: 0 + 0 + ... = 0. ✓
Watch out. Do not write the other number. Multiplying by 0 always gives 0, not the number you started with.
Method. Each hop is 4. Add 4 to the number before each box. The last number on the line is 6 × 4.
- Find the size of each hop. The labels at the start show it.0 to 4: each hop is 4.
- Fill the boxes. Add 4 to the number before the box.12 + 4 = 16
20 is the next number, and 20 + 4 = 24 - Say what 6 × 4 is. There are 6 hops, so the last number is 6 × 4.6 × 4 = 24
Check. Count in 4s: 4, 8, 12, 16, 20, 24. Six numbers. ✓
Watch out. There are 6 hops but 7 numbers on the line, because the line starts at 0.
Watch out
Be careful with 0 and 1. 7 × 1 is 7 (not 1) and 7 × 0 is 0 (not 7). Also, do not mix up rows and columns: 3 rows of 4 is 3 × 4, and 4 rows of 3 is 4 × 3. The answer is the same, but they are different pictures.Exercise 3A Groups, arrays, swapping and multiplying by 0 and 1
Non-calculatorKey words. Multiplication is a quick way to add equal groups. A group is a set of things together.
Method. Count the groups and how many are in each group. All the groups are equal, so you can add them up or multiply.
- Count the groups. Each box is one group.There are 3 boxes.
- Count how many are in each group. The groups are equal, so count in one group only.Each box has 5 dots.
- Write it as an addition. Equal groups can be added.5 + 5 + 5 = 15
- Write it as a multiplication. 3 groups of 5 is 3 × 5.3 × 5 = 15
Check. Count in 5s: 5, 10, 15. The last number is 15. ✓
Watch out. The first number says how many groups. The second number says how many in each group.
Key words. Multiplication is a quick way to add equal groups. A group is a set of things together.
Method. Count the groups and how many are in each group. All the groups are equal, so you can add them up or multiply.
- Count the groups. Each box is one group.There are 6 boxes.
- Count how many are in each group. The groups are equal, so count in one group only.Each box has 2 dots.
- Write it as an addition. Equal groups can be added.2 + 2 + 2 + 2 + 2 + 2 = 12
- Write it as a multiplication. 6 groups of 2 is 6 × 2.6 × 2 = 12
Check. Count in 2s: 2, 4, 6, 8, 10, 12. The last number is 12. ✓
Watch out. The first number says how many groups. The second number says how many in each group.
Key words. Multiplication is a quick way to add equal groups. A group is a set of things together.
Method. Count the groups and how many are in each group. All the groups are equal, so you can add them up or multiply.
- Count the groups. Each box is one group.There are 4 boxes.
- Count how many are in each group. The groups are equal, so count in one group only.Each box has 4 dots.
- Write it as an addition. Equal groups can be added.4 + 4 + 4 + 4 = 16
- Write it as a multiplication. 4 groups of 4 is 4 × 4.4 × 4 = 16
Check. Count in 4s: 4, 8, 12, 16. The last number is 16. ✓
Watch out. The first number says how many groups. The second number says how many in each group.
Key words. Multiplication is a quick way to add equal groups. A group is a set of things together.
Method. Count the groups and how many are in each group. All the groups are equal, so you can add them up or multiply.
- Count the groups. Each box is one group.There are 5 boxes.
- Count how many are in each group. The groups are equal, so count in one group only.Each box has 3 dots.
- Write it as an addition. Equal groups can be added.3 + 3 + 3 + 3 + 3 = 15
- Write it as a multiplication. 5 groups of 3 is 5 × 3.5 × 3 = 15
Check. Count in 3s: 3, 6, 9, 12, 15. The last number is 15. ✓
Watch out. The first number says how many groups. The second number says how many in each group.
Key words. An array is dots or objects in rows and columns. Rows go across and columns go down.
Method. Count the rows and the columns. An array with r rows and c dots in each row has r × c dots.
- Count the rows. Rows go across.There are 2 rows.
- Count the columns. Columns go down. Each row has the same number of dots.There are 9 columns.
- Write the multiplication. 2 rows of 9 is 2 × 9. Count in 9s, 2 times.9, 18
2 × 9 = 18 - Turn the array on its side. Now there are 9 rows of 2. The total is the same.9 × 2 = 18
Check. Count in 2s instead: 2, 4, 6, 8, 10, 12, 14, 16, 18. ✓
Watch out. The total is the same both ways round, but the sentence is different. 3 rows of 4 is 3 × 4.
Key words. An array is dots or objects in rows and columns. Rows go across and columns go down.
Method. Count the rows and the columns. An array with r rows and c dots in each row has r × c dots.
- Count the rows. Rows go across.There are 3 rows.
- Count the columns. Columns go down. Each row has the same number of dots.There are 7 columns.
- Write the multiplication. 3 rows of 7 is 3 × 7. Count in 7s, 3 times.7, 14, 21
3 × 7 = 21 - Turn the array on its side. Now there are 7 rows of 3. The total is the same.7 × 3 = 21
Check. Count in 3s instead: 3, 6, 9, 12, 15, 18, 21. ✓
Watch out. The total is the same both ways round, but the sentence is different. 3 rows of 4 is 3 × 4.
Key words. An array is dots or objects in rows and columns. Rows go across and columns go down.
Method. Count the rows and the columns. An array with r rows and c dots in each row has r × c dots.
- Count the rows. Rows go across.There are 5 rows.
- Count the columns. Columns go down. Each row has the same number of dots.There are 6 columns.
- Write the multiplication. 5 rows of 6 is 5 × 6. Count in 6s, 5 times.6, 12, 18, 24, 30
5 × 6 = 30 - Turn the array on its side. Now there are 6 rows of 5. The total is the same.6 × 5 = 30
Check. Count in 5s instead: 5, 10, 15, 20, 25, 30. ✓
Watch out. The total is the same both ways round, but the sentence is different. 3 rows of 4 is 3 × 4.
Key words. An array is dots or objects in rows and columns. Rows go across and columns go down.
Method. Count the rows and the columns. An array with r rows and c dots in each row has r × c dots.
- Count the rows. Rows go across.There are 4 rows.
- Count the columns. Columns go down. Each row has the same number of dots.There are 8 columns.
- Write the multiplication. 4 rows of 8 is 4 × 8. Count in 8s, 4 times.8, 16, 24, 32
4 × 8 = 32 - Turn the array on its side. Now there are 8 rows of 4. The total is the same.8 × 4 = 32
Check. Count in 4s instead: 4, 8, 12, 16, 20, 24, 28, 32. ✓
Watch out. The total is the same both ways round, but the sentence is different. 3 rows of 4 is 3 × 4.
(a) 7 + 7 + 7 + 7 (b) 5 + 5 + 5 + 5 + 5 + 5 (c) 9 + 9 + 9 (d) 10 + 10 + 10 + 10 + 10
Method. Adding the same number again and again is a multiplication. Count how many times the number is added.
- Count how many numbers are being added. The number 7 appears each time.7 appears 4 times.
- Write it as a multiplication. 4 lots of 7 is 4 × 7.4 × 7
- Work out the answer. Use a times table fact.7 + 7 = 14
double 10 = 20, double 4 = 8, so 20 + 8 = 28
4 × 7 = 28
Check. Add them up: 7 + 7 + 7 + 7 = 28. ✓
Watch out. Count the numbers carefully. 4 lots of 7 is 4 × 7, not 7 × 4 (though the total is the same).
Method. Adding the same number again and again is a multiplication. Count how many times the number is added.
- Count how many numbers are being added. The number 5 appears each time.5 appears 6 times.
- Write it as a multiplication. 6 lots of 5 is 6 × 5.6 × 5
- Work out the answer. Use a times table fact.10 × 6 = 60
half of 60 = 30
6 × 5 = 30
Check. Add them up: 5 + 5 + 5 + 5 + 5 + 5 = 30. ✓
Watch out. Count the numbers carefully. 6 lots of 5 is 6 × 5, not 5 × 6 (though the total is the same).
Method. Adding the same number again and again is a multiplication. Count how many times the number is added.
- Count how many numbers are being added. The number 9 appears each time.9 appears 3 times.
- Write it as a multiplication. 3 lots of 9 is 3 × 9.3 × 9
- Work out the answer. Use a times table fact.10 × 3 = 30
30 − 3 = 27
3 × 9 = 27
Check. Add them up: 9 + 9 + 9 = 27. ✓
Watch out. Count the numbers carefully. 3 lots of 9 is 3 × 9, not 9 × 3 (though the total is the same).
Method. Adding the same number again and again is a multiplication. Count how many times the number is added.
- Count how many numbers are being added. The number 10 appears each time.10 appears 5 times.
- Write it as a multiplication. 5 lots of 10 is 5 × 10.5 × 10
- Work out the answer. Use a times table fact.5 tens
5 → 50
5 × 10 = 50
Check. Add them up: 10 + 10 + 10 + 10 + 10 = 50. ✓
Watch out. Count the numbers carefully. 5 lots of 10 is 5 × 10, not 10 × 5 (though the total is the same).
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?3 to 6: 6 − 3 = 3. We are counting in 3s.
- Fill each gap. Add 3 to the number before the gap.6 + 3 = 9
12 + 3 = 15 - Say the whole sequence. Read it from the start to check it sounds right.3, 6, 9, 12, 15, 18
Check. Every number is a multiple of 3: 3, 6, 9, 12, 15, 18. ✓
Watch out. Check each jump is the same size (3), including the jump into and out of each gap.
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?20 to 24: 24 − 20 = 4. We are counting in 4s.
- Fill each gap. Add 4 to the number before the gap.4 + 4 = 8
12 + 4 = 16 - Say the whole sequence. Read it from the start to check it sounds right.4, 8, 12, 16, 20, 24
Check. Every number is a multiple of 4: 4, 8, 12, 16, 20, 24. ✓
Watch out. Check each jump is the same size (4), including the jump into and out of each gap.
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?5 to 10: 10 − 5 = 5. We are counting in 5s.
- Fill each gap. Add 5 to the number before the gap.15 + 5 = 20
25 + 5 = 30
35 + 5 = 40 - Say the whole sequence. Read it from the start to check it sounds right.5, 10, 15, 20, 25, 30, 35, 40
Check. Every number is a multiple of 5: 5, 10, 15, 20, 25, 30, 35, 40. ✓
Watch out. Check each jump is the same size (5), including the jump into and out of each gap.
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?2 to 4: 4 − 2 = 2. We are counting in 2s.
- Fill each gap. Add 2 to the number before the gap.4 + 2 = 6
8 + 2 = 10
12 + 2 = 14 - Say the whole sequence. Read it from the start to check it sounds right.2, 4, 6, 8, 10, 12, 14, 16
Check. Every number is a multiple of 2: 2, 4, 6, 8, 10, 12, 14, 16. ✓
Watch out. Check each jump is the same size (2), including the jump into and out of each gap.
Key words. Commutative means that the order does not change the answer. Multiplication is commutative.
Method. Multiplication can be done in either order. The same two numbers give the same answer.
- Look at the numbers you can see. Both sides must use 6 and 4.6 × 4 = 4 × ?
- Use the idea that order does not matter. 6 × 4 = 4 × 6.6 × 4 = 24 and 4 × 6 = 24
- Write the missing number. It is the number that is not already on that side.The missing number is 6.
Check. Work out both sides: they are both 24. ✓
Watch out. This only works for multiplication. 8 − 3 is not the same as 3 − 8.
Key words. Commutative means that the order does not change the answer. Multiplication is commutative.
Method. Multiplication can be done in either order. The same two numbers give the same answer.
- Look at the numbers you can see. Both sides must use 7 and 9.7 × ? = 9 × 7
- Use the idea that order does not matter. 7 × 9 = 9 × 7.7 × 9 = 63 and 9 × 7 = 63
- Write the missing number. It is the number that is not already on that side.The missing number is 9.
Check. Work out both sides: they are both 63. ✓
Watch out. This only works for multiplication. 8 − 3 is not the same as 3 − 8.
Key words. Commutative means that the order does not change the answer. Multiplication is commutative.
Method. Multiplication can be done in either order. The same two numbers give the same answer.
- Look at the numbers you can see. Both sides must use 8 and 3.? × 8 = 8 × 3
- Use the idea that order does not matter. 8 × 3 = 3 × 8.8 × 3 = 24 and 3 × 8 = 24
- Write the missing number. It is the number that is not already on that side.The missing number is 3.
Check. Work out both sides: they are both 24. ✓
Watch out. This only works for multiplication. 8 − 3 is not the same as 3 − 8.
Key words. Commutative means that the order does not change the answer. Multiplication is commutative.
Method. Multiplication can be done in either order. The same two numbers give the same answer.
- Look at the numbers you can see. Both sides must use 5 and 12.5 × 12 = ? × 5
- Use the idea that order does not matter. 5 × 12 = 12 × 5.5 × 12 = 60 and 12 × 5 = 60
- Write the missing number. It is the number that is not already on that side.The missing number is 12.
Check. Work out both sides: they are both 60. ✓
Watch out. This only works for multiplication. 8 − 3 is not the same as 3 − 8.
Method. Multiplying by 1 leaves the number the same.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 1 = 1 × 7. Use the 1 times table trick.7 × 1 = 1 × 7
- Say what the multiplication means. 1 group of 7 is just 7.1 group of 7 = 7
- Write the answer. 7 × 1 = 7
Check. 7 groups of 1, or 1 groups of 7: both are 7. ✓
Watch out. Multiplying by 1 does not change the number. It does not make it 0 or 1.
Method. Zero groups, or groups with nothing in them, always make 0 in total.
- Say what the multiplication means. 0 × 9 means 0 groups of 9. There are no groups, so there is nothing.0 groups of 9 = 0
- Write the answer. Anything multiplied by 0 is 0.0 × 9 = 0
Check. Adding groups: 0 + 0 + ... = 0. ✓
Watch out. Do not write the other number. Multiplying by 0 always gives 0, not the number you started with.
Method. Multiplying by 1 leaves the number the same.
- Say what the multiplication means. 1 group of 12 is just 12.1 group of 12 = 12
- Write the answer. 1 × 12 = 12
Check. 1 groups of 12, or 12 groups of 1: both are 12. ✓
Watch out. Multiplying by 1 does not change the number. It does not make it 0 or 1.
Method. Zero groups, or groups with nothing in them, always make 0 in total.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 0 = 0 × 12. Use the 0 times table trick.12 × 0 = 0 × 12
- Say what the multiplication means. 0 × 12 means 0 groups of 12. There are no groups, so there is nothing.0 groups of 12 = 0
- Write the answer. Anything multiplied by 0 is 0.12 × 0 = 0
Check. Adding groups: 0 + 0 + ... = 0. ✓
Watch out. Do not write the other number. Multiplying by 0 always gives 0, not the number you started with.
Method. Multiplying by 1 leaves the number the same.
- Say what the multiplication means. 1 group of 1 is just 1.1 group of 1 = 1
- Write the answer. 1 × 1 = 1
Check. 1 groups of 1, or 1 groups of 1: both are 1. ✓
Watch out. Multiplying by 1 does not change the number. It does not make it 0 or 1.
Method. Zero groups, or groups with nothing in them, always make 0 in total.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 0 = 0 × 8. Use the 0 times table trick.8 × 0 = 0 × 8
- Say what the multiplication means. 0 × 8 means 0 groups of 8. There are no groups, so there is nothing.0 groups of 8 = 0
- Write the answer. Anything multiplied by 0 is 0.8 × 0 = 0
Check. Adding groups: 0 + 0 + ... = 0. ✓
Watch out. Do not write the other number. Multiplying by 0 always gives 0, not the number you started with.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 2 = 2 × 3. Use the 2 times table trick.3 × 2 = 2 × 3
- Double the number. Doubling means adding the number to itself.3 + 3 = 6
- Write the answer. 3 × 2 = 6
Check. Check by dividing: 6 ÷ 2 = 3. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 4 = 40
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 4 = 20
Check. Check by dividing: 20 ÷ 4 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 6 means 6 lots of 10, which is 6 tens.6 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.6 → 60
- Write the answer. 10 × 6 = 60
Check. Check by dividing: 60 ÷ 6 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.9 + 9 = 18
- Write the answer. 2 × 9 = 18
Check. The digits of 18 add up to 9: 1 + 8 = 9. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 7 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 10 means 10 lots of 10, which is 10 tens.10 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.10 → 100
- Write the answer. 10 × 10 = 100
Check. Check by dividing: 100 ÷ 10 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 5 = 5 × 4. Use the 5 times table trick.4 × 5 = 5 × 4
- Multiply by 10. This is easy: move the digits one place to the left.10 × 4 = 40
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20
- Write the answer. Answers in the 5 times table end in 0 or 5.4 × 5 = 20
Check. Check by dividing: 20 ÷ 4 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.8 + 8 = 16
- Write the answer. 2 × 8 = 16
Check. Check by dividing: 16 ÷ 2 = 8. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. There are 5 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 5 equal bars show 5 equal boxes. Each bar is 6. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.5 × 6
- Work it out. Use a times table trick.10 × 6 = 60
half of 60 = 30
5 × 6 = 30 - Write the answer. Include the unit.30 eggs
Check. Divide back: 30 ÷ 5 = 6. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 4 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 4 equal bars show 4 equal spiders. Each bar is 8. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.4 × 8
- Work it out. Use a times table trick.8 + 8 = 16
double 10 = 20, double 6 = 12, so 20 + 12 = 32
4 × 8 = 32 - Write the answer. Include the unit.32 legs
Check. Divide back: 32 ÷ 4 = 8. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Look at the array. Equal rows are equal groups, so we multiply, we do not add the two numbers.
- Look at what Zainab did. She added the number of rows and the number in each row.3 + 8 = 11
- Say why that is wrong. 3 rows of 8 means 3 groups of 8. We need 8 + 8 + 8, or 3 × 8.8 + 8 + 8 = 24
- Multiply to find the number of chairs. Count in 8s: 8, 16, 24.3 × 8 = 24
Check. Turn the array round: 8 rows of 3 is 8 × 3 = 24. ✓
Watch out. “Rows and columns” means equal groups. Multiply the two numbers, do not add them.
Method. Try some numbers. If the rule works for every number you try, it is probably always true.
- Try some examples. 1 group of a number is just that number.1 × 4 = 4 1 × 12 = 12 9 × 1 = 9 100 × 1 = 100
- Explain why. Multiplying by 1 means one group, and one group of any number is just that number.It does not matter which number you start with.
- Decide. Always
Check. Check with an array: 1 row of 6 dots has 6 dots. ✓
Watch out. “Always” means it works every time. One example is not enough to prove it, so give a reason too.
Method. Work out each one. The odd one out has a different answer from the others.
- Work out A and B. Both use the numbers 4 and 6. Order does not matter.4 × 6 = 24 and 6 × 4 = 24
- Work out C. This one is an addition, not a multiplication.4 + 6 = 10
- Work out D. 2 groups of 12.2 × 12 = 24
- Choose the odd one out. A, B and D all make 24. C makes 10.C (4 + 6)
Check. Count in 4s six times: 4, 8, 12, 16, 20, 24. ✓
Watch out. Check the sign (+ or ×) as well as the numbers.
Method. Think about what 9 × 0 means: 9 groups, and each group has 0 in it.
- Say what the multiplication means. 9 × 0 is 9 groups of 0.0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0
- Add the groups. Adding 0 nine times does not make anything.0 + 0 + ... + 0 = 0
- Answer Amira. There are nine groups, but nothing in them.No. 9 × 0 = 0
Check. Swap the order: 0 × 9 = 0 groups of 9 = 0. ✓
Watch out. Anything multiplied by 0 is 0. The number of groups does not matter if each group is empty.
Method. Look for pairs of numbers that multiply to make 12. Each pair makes an array. Turning the array gives a second array.
- Try 1 row. 12 dots in one long row.1 × 12 = 12
- Try 2 rows. Divide 12 into 2 equal rows.2 × 6 = 12
- Try 3 rows. 3 × 4 = 12
- Try 4, 5, 6... rows. 4 rows gives 4 × 3, which is the 3-row array turned round. 5 does not fit (5 × 2 = 10 and 5 × 3 = 15). 6 rows gives 6 × 2.4 × 3 = 12 6 × 2 = 12 12 × 1 = 12
- Count the arrays. The pictures show 3 different shapes. None of them is a square, so each shape can be turned to make a second array.3 shapes × 2 = 6 arrays
Check. Each fact has its partner: 1 × 12 and 12 × 1, 2 × 6 and 6 × 2, 3 × 4 and 4 × 3. ✓
Watch out. Check that every row has the same number of dots. No gaps and no leftover dots.
The 2, 4, 8, 5 and 10 times tables
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
You already know many of these tables from Year 3. Now we go all the way up to 12 × 12, and we use tricks so that you can work out any fact quickly. The first set of tricks uses doubling, halving and tens.
The 2 times table: double. Multiplying by 2 is the same as doubling. 2 × 7 means 7 + 7 = 14. Every answer in the 2 times table is an even number.
The 10 times table: move the digits. Multiplying by 10 makes every digit ten times bigger, so every digit moves one place to the left and a 0 goes in the ones place. 10 × 7 = 70. 10 × 12 = 120 (12 tens). Every answer in the 10 times table ends in 0.
The 5 times table: half of the 10 times table. 5 is half of 10, so 5 × 8 is half of 10 × 8. 10 × 8 = 80 and half of 80 is 40. So 5 × 8 = 40. Every answer in the 5 times table ends in 0 or 5.
The 4 times table: double double. 4 × 7: double 7 is 14, and double 14 is 28. So 4 × 7 = 28. The 8 times table: double double double. 8 × 7: double 7 is 14, double 14 is 28, double 28 is 56. So 8 × 7 = 56. The answers in the 4 and 8 times tables are always even.
Key words. To double a number is to multiply it by 2. To halve a number is to share it into 2 equal parts. A multiple of a number is an answer in its times table, such as 8, 16, 24 for 8.
Key ideas
- × 2: double the number.
- × 10: move every digit one place to the left (10 × 12 = 120).
- × 5: find × 10 first, then halve it.
- × 4: double, then double again.
- × 8: double three times.
- Use commutativity: 12 × 5 = 5 × 12, so use the table you know best.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 2 = 2 × 12. Use the 2 times table trick.12 × 2 = 2 × 12
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 12 × 2 = 24
Check. Check by dividing: 24 ÷ 2 = 12. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 10 = 10 × 11. Use the 10 times table trick.11 × 10 = 10 × 11
- Think about tens. 10 × 11 means 11 lots of 10, which is 11 tens.11 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.11 → 110
- Write the answer. 11 × 10 = 110
Check. Check by dividing: 110 ÷ 10 = 11. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 5 = 5 × 9. Use the 5 times table trick.9 × 5 = 5 × 9
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.9 × 5 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 4 = 4 × 7. Use the 4 times table trick.7 × 4 = 4 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Write the answer. 7 × 4 = 28
Check. Check by dividing: 28 ÷ 4 = 7. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 4 = 4 × 12. Use the 4 times table trick.12 × 4 = 4 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 12 × 4 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 8 = 8 × 6. Use the 8 times table trick.6 × 8 = 8 × 6
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 12 × 8 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Watch out
Doubling is not adding 2. To double 7 you add 7 + 7 = 14. Also, for the 5 times table, find 10 × the number first, then halve it. And for the 4 and 8 times tables, count your doubles: two doubles for 4, three doubles for 8.Exercise 3B The 2, 4, 5, 8 and 10 times tables
Non-calculatorMethod. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.6 + 6 = 12
- Write the answer. 2 × 6 = 12
Check. Check by dividing: 12 ÷ 2 = 6. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 7 means 7 lots of 10, which is 7 tens.7 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.7 → 70
- Write the answer. 10 × 7 = 70
Check. Check by dividing: 70 ÷ 7 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 1 = 2, so 20 + 2 = 22
- Write the answer. 2 × 11 = 22
Check. Check by dividing: 22 ÷ 2 = 11. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 12 means 12 lots of 10, which is 12 tens.12 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.12 → 120
- Write the answer. 10 × 12 = 120
Check. Check by dividing: 120 ÷ 10 = 12. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 2 = 2 × 9. Use the 2 times table trick.9 × 2 = 2 × 9
- Double the number. Doubling means adding the number to itself.9 + 9 = 18
- Write the answer. 9 × 2 = 18
Check. The digits of 18 add up to 9: 1 + 8 = 9. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 9 means 9 lots of 10, which is 9 tens.9 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.9 → 90
- Write the answer. 10 × 9 = 90
Check. The digits of 90 add up to 9: 9 + 0 = 9. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 2 = 2 × 12. Use the 2 times table trick.12 × 2 = 2 × 12
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 12 × 2 = 24
Check. Check by dividing: 24 ÷ 2 = 12. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 10 = 10 × 4. Use the 10 times table trick.4 × 10 = 10 × 4
- Think about tens. 10 × 4 means 4 lots of 10, which is 4 tens.4 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.4 → 40
- Write the answer. 4 × 10 = 40
Check. Check by dividing: 40 ÷ 4 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 11 means 11 lots of 10, which is 11 tens.11 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.11 → 110
- Write the answer. 10 × 11 = 110
Check. Check by dividing: 110 ÷ 10 = 11. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.8 + 8 = 16
- Write the answer. 2 × 8 = 16
Check. Check by dividing: 16 ÷ 2 = 8. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 6 = 60
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 6 = 30
Check. Check by dividing: 30 ÷ 5 = 6. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 9 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 11 = 110
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 100 = 50, half of 10 = 5, so 50 + 5 = 55
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 11 = 55
Check. Check by dividing: 55 ÷ 5 = 11. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 5 = 5 × 7. Use the 5 times table trick.7 × 5 = 5 × 7
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.7 × 5 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 12 = 120
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 120 = 60
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 12 = 60
Check. Check by dividing: 60 ÷ 5 = 12. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 5 = 5 × 8. Use the 5 times table trick.8 × 5 = 5 × 8
- Multiply by 10. This is easy: move the digits one place to the left.10 × 8 = 80
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40
- Write the answer. Answers in the 5 times table end in 0 or 5.8 × 5 = 40
Check. Check by dividing: 40 ÷ 5 = 8. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 4 = 40
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 4 = 20
Check. Check by dividing: 20 ÷ 4 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 5 = 5 × 3. Use the 5 times table trick.3 × 5 = 5 × 3
- Multiply by 10. This is easy: move the digits one place to the left.10 × 3 = 30
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 20 = 10, half of 10 = 5, so 10 + 5 = 15
- Write the answer. Answers in the 5 times table end in 0 or 5.3 × 5 = 15
Check. Check by dividing: 15 ÷ 3 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 5 × 10 = 10 × 5. Use the 10 times table trick.5 × 10 = 10 × 5
- Think about tens. 10 × 5 means 5 lots of 10, which is 5 tens.5 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.5 → 50
- Write the answer. 5 × 10 = 50
Check. Check by dividing: 50 ÷ 5 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 7 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.6 + 6 = 12
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 4 × 6 = 24
Check. Check by dividing: 24 ÷ 4 = 6. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.9 + 9 = 18
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 8 = 16, so 20 + 16 = 36
- Write the answer. 4 × 9 = 36
Check. The digits of 36 add up to 9: 3 + 6 = 9. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 4 = 4 × 7. Use the 4 times table trick.7 × 4 = 4 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Write the answer. 7 × 4 = 28
Check. Check by dividing: 28 ÷ 4 = 7. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 11 = 11 × 4. Use the 11 times table trick.4 × 11 = 11 × 4
- Multiply by 10. 10 lots of the number first.10 × 4 = 40
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 44.40 + 4 = 44
- Write the answer. 4 × 11 = 44
Check. Check by dividing: 44 ÷ 4 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 4 × 12 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 4 = 4 × 8. Use the 4 times table trick.8 × 4 = 4 × 8
- Double the number. This gives 2 lots.8 + 8 = 16
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Write the answer. 8 × 4 = 32
Check. Check by dividing: 32 ÷ 4 = 8. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.3 + 3 = 6
- Double the answer again. Doubling twice gives 4 lots.6 + 6 = 12
- Write the answer. 4 × 3 = 12
Check. Check by dividing: 12 ÷ 3 = 4. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 4 = 40
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 4 = 20
Check. Check by dividing: 20 ÷ 4 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 8 × 6 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 9 = 9 × 8. Use the 9 times table trick.8 × 9 = 9 × 8
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Take away one group. 9 = 10 − 1, so take away the number itself once.80 − 8 = 72
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).8 × 9 = 72
Check. The digits of 72 add up to 9: 7 + 2 = 9. ✓
Watch out. Take away 8, the other number, not 9. For 9 × 8 you work out 10 × 8 − 8.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 8 = 8 × 7. Use the 8 times table trick.7 × 8 = 8 × 7
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 11 = 11 × 8. Use the 11 times table trick.8 × 11 = 11 × 8
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 88.80 + 8 = 88
- Write the answer. 8 × 11 = 88
Check. Check by dividing: 88 ÷ 8 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 12 = 12 × 8. Use the 12 times table trick.8 × 12 = 12 × 8
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 8 × 12 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.8 + 8 = 16
- Double again. This gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Double a third time. This gives 8 lots.double 30 = 60, double 2 = 4, so 60 + 4 = 64
- Write the answer. 8 × 8 = 64
Check. Check by dividing: 64 ÷ 8 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 3 = 3 × 8. Use the 3 times table trick.8 × 3 = 3 × 8
- Double the number. This gives 2 lots.8 + 8 = 16
- Add one more group. 3 = 2 + 1, so add the number once more.16 + 8 = 24
- Write the answer. 8 × 3 = 24
Check. Check by dividing: 24 ÷ 3 = 8. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.8 + 8 = 16
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Write the answer. 4 × 8 = 32
Check. Check by dividing: 32 ÷ 4 = 8. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 8 × 7 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 5 = 5 × 12. Use the 5 times table trick.12 × 5 = 5 × 12
- Multiply by 10. This is easy: move the digits one place to the left.10 × 12 = 120
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 120 = 60
- Write the answer. Answers in the 5 times table end in 0 or 5.12 × 5 = 60
Check. Check by dividing: 60 ÷ 5 = 12. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.8 + 8 = 16
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Write the answer. 4 × 8 = 32
Check. Check by dividing: 32 ÷ 4 = 8. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 8 means 8 lots of 10, which is 8 tens.8 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.8 → 80
- Write the answer. 10 × 8 = 80
Check. Check by dividing: 80 ÷ 8 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 4 = 4 × 6. Use the 4 times table trick.6 × 4 = 4 × 6
- Double the number. This gives 2 lots.6 + 6 = 12
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 6 × 4 = 24
Check. Check by dividing: 24 ÷ 4 = 6. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Take away one group. 9 = 10 − 1, so take away the number itself once.80 − 8 = 72
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 8 = 72
Check. The digits of 72 add up to 9: 7 + 2 = 9. ✓
Watch out. Take away 8, the other number, not 9. For 9 × 8 you work out 10 × 8 − 8.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 2 × 12 = 24
Check. Check by dividing: 24 ÷ 2 = 12. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 5 = 5 × 11. Use the 5 times table trick.11 × 5 = 5 × 11
- Multiply by 10. This is easy: move the digits one place to the left.10 × 11 = 110
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 100 = 50, half of 10 = 5, so 50 + 5 = 55
- Write the answer. Answers in the 5 times table end in 0 or 5.11 × 5 = 55
Check. Check by dividing: 55 ÷ 5 = 11. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 4 = 4 × 12. Use the 4 times table trick.12 × 4 = 4 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 12 × 4 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 8 = 80
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 8 = 40
Check. Check by dividing: 40 ÷ 5 = 8. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 10 = 10 × 7. Use the 10 times table trick.7 × 10 = 10 × 7
- Think about tens. 10 × 7 means 7 lots of 10, which is 7 tens.7 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.7 → 70
- Write the answer. 7 × 10 = 70
Check. Check by dividing: 70 ÷ 7 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 2 = 2 × 8. Use the 2 times table trick.8 × 2 = 2 × 8
- Double the number. Doubling means adding the number to itself.8 + 8 = 16
- Write the answer. 8 × 2 = 16
Check. Check by dividing: 16 ÷ 2 = 8. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 8 is multiplied by to make 56.8 × ? = 56
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 56 by 8.56 ÷ 8 = 7
- Write the missing number. 8 × 7 = 56
Check. Put it back: 8 × 7 = 56. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 4, makes 36.? × 4 = 36
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 36 by 4.36 ÷ 4 = 9
- Write the missing number. 9 × 4 = 36
Check. Put it back: 9 × 4 = 36. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 5 is multiplied by to make 45.5 × ? = 45
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 45 by 5.45 ÷ 5 = 9
- Write the missing number. 5 × 9 = 45
Check. Put it back: 5 × 9 = 45. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 10, makes 120.? × 10 = 120
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 120 by 10.120 ÷ 10 = 12
- Write the missing number. 12 × 10 = 120
Check. Put it back: 12 × 10 = 120. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 4 is multiplied by to make 48.4 × ? = 48
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 48 by 4.48 ÷ 4 = 12
- Write the missing number. 4 × 12 = 48
Check. Put it back: 4 × 12 = 48. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 8, makes 72.? × 8 = 72
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 72 by 8.72 ÷ 8 = 9
- Write the missing number. 9 × 8 = 72
Check. Put it back: 9 × 8 = 72. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Each hop on the number line is the same size. Work out the size of one hop, then add it on.
- Find the size of each hop. The labels at the start show it.0 to 8: each hop is 8.
- Fill each box. Add 8 to the number before the box.8 + 8 = 16
32 + 8 = 40
48 + 8 = 56 - Write the missing numbers. 16, 40, 56
Check. The last number is 8 × 8 = 64. ✓
Watch out. Count the hops, not the numbers. There is a number at the start (0).
Method. Start with 7. Double it three times. Then say which multiplication this is.
- Double 7. Doubling means adding the number to itself.7 + 7 = 14
- Double again. Use the new answer.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Say which multiplication it is. Doubling three times means multiplying by 2, then 2, then 2. That is the same as multiplying by 8.7 × 8 = 56
Check. Use the 5 and 2 trick: 7 × 5 = 35 and 7 × 2 = 14. 35 + 14 = 49, so 7 × 7 = 49, and 49 + 7 = 56. ✓
Watch out. Write each double clearly. It is easy to lose track of which double you are on.
Method. There are 9 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 9 equal bars show 9 equal packs. Each bar is 4. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.9 × 4
- Work it out. Use a times table trick.9 + 9 = 18
double 10 = 20, double 8 = 16, so 20 + 16 = 36
9 × 4 = 36 - Write the answer. Include the unit.36 pens
Check. Divide back: 36 ÷ 9 = 4. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 8 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 8 equal bars show 8 equal tickets. Each bar is £5. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.8 × £5
- Work it out. Use a times table trick.10 × 8 = 80
half of 80 = 40
8 × 5 = 40 - Write the answer. Include the unit.£40
Check. Divide back: 40 ÷ 8 = 5. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 12 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 12 equal bars show 12 equal boxes. Each bar is 8. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.12 × 8
- Work it out. Use a times table trick.10 × 8 = 80
8 + 8 = 16
80 + 16 = 96
12 × 8 = 96 - Write the answer. Include the unit.96 pencils
Check. Divide back: 96 ÷ 12 = 8. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Work out 4 × 6 and 8 × 6 and see if one is double the other.
- Work out 4 × 6. Double 6, then double again.6 + 6 = 12, double 12 = 24, so 4 × 6 = 24
- Double it. Doubling the number of groups doubles the total.double 24 = 48
- Work out 8 × 6. Double three times.6 + 6 = 12, double 12 = 24, double 24 = 48, so 8 × 6 = 48
- Compare. 48 = 48, so yes, 8 × 6 is double 4 × 6.
Check. 8 is double 4. So 8 lots of anything is double 4 lots. ✓
Watch out. Only the number of groups doubles (4 → 8). The size of each group (6) stays the same.
Method. Check the 10 times table.
- List some. 10 times a number makes tens, so the ones digit is 0.10, 20, 30, 40, ... 100, 110, 120
- Decide. The ones digit is 0 every time.Always
Check. 10 × 12 = 120 ends in 0. ✓
Watch out. “Always” needs a reason, not just a few examples.
Method. Write the 5 times table and look at the last digit.
- List the 5 times table. Look at the ones digits.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60
- Decide. 5 ends in 5, but 10 ends in 0.Sometimes: they end in 5 or 0.
Check. The ones digits go 5, 0, 5, 0, ... so only half end in 5. ✓
Watch out. “Sometimes” needs an example that works and one that does not.
Method. List the numbers in both times tables that are between 30 and 50. Look for a number that is in both lists.
- List the 4 times table between 30 and 50. Count up in 4s.32, 36, 40, 44, 48
- List the 5 times table between 30 and 50. Count up in 5s.35, 40, 45
- Find the number in both lists. 40
Check. 4 × 10 = 40 and 5 × 8 = 40. ✓
Watch out. Check the number is in both tables, not just one.
The 3, 6, 9 and 12 times tables
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
These tables are a bit harder, but each one has a good trick.
The 3 times table: double and one more. 3 × 7: double 7 is 14, and one more 7 makes 21. So 3 × 7 = 21. A pattern to spot: the digits of every answer add up to 3, 6 or 9. For example, 24 gives 2 + 4 = 6, and 33 gives 3 + 3 = 6.
The 6 times table: 5 lots and one more. 6 × 7: 5 × 7 = 35, and one more 7 makes 42. You can also double the 3 times table: 3 × 7 = 21, and double 21 is 42. Every answer in the 6 times table is even.
The 9 times table: ten lots, take away one lot. 9 × 7: 10 × 7 = 70, and 70 − 7 = 63. Look for the pattern in the answers: the tens digit goes up by 1 each time and the ones digit goes down by 1. The two digits always add up to 9.
The finger trick for 9 × 1 to 9 × 10. Hold up all ten fingers and number them 1 to 10 from the left. To work out 9 × 7, fold down finger 7. There are 6 fingers on the left (6 tens) and 3 fingers on the right (3 ones). The answer is 63.
The 12 times table: ten lots and two lots. 12 × 7: 10 × 7 = 70 and 2 × 7 = 14, so 70 + 14 = 84. A dozen is 12, so a dozen eggs is 12 eggs.
Key ideas
- × 3: double the number, then add the number once more.
- × 6: do × 5 and add one more group (or double the 3 times table).
- × 9: do × 10, then take away the number once. The digits of the answer add up to 9.
- × 12: do × 10 and × 2, then add.
- Finger trick for 9s: fold down the finger you are multiplying by. Fingers on the left are tens, fingers on the right are ones.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.8 + 8 = 16
- Add one more group. 3 = 2 + 1, so add the number once more.16 + 8 = 24
- Write the answer. 3 × 8 = 24
Check. Check by dividing: 24 ÷ 3 = 8. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 6 = 6 × 7. Use the 6 times table trick.7 × 6 = 6 × 7
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 7 × 6 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 6 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 11 = 11 × 9. Use the 11 times table trick.9 × 11 = 11 × 9
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 99.90 + 9 = 99
- Write the answer. 9 × 11 = 99
Check. The digits of 99 add up to 9: 9 + 9 = 18. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 7 = 70
- Multiply by 2. Double the number.7 + 7 = 14
- Add the two answers together. 12 = 10 + 2.70 + 14 = 84
- Write the answer. 12 × 7 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 12 × 6 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Hold up all ten fingers. Fold down the finger that matches the number you are multiplying 9 by. The fingers either side give the answer.
- Hold up ten fingers and number them 1 to 10. Number the fingers from left to right. Fold down finger 7.
- Count the fingers on the left of the folded finger. This is the number of tens.6 fingers on the left = 6 tens
- Count the fingers on the right of the folded finger. This is the number of ones.3 fingers on the right = 3 ones
- Write the tens and ones together. 9 × 7 = 63
Check. Use the other method: 10 × 7 = 70, then 70 − 7 = 63. ✓
Watch out. The folded finger is not counted. Count only the fingers that are still up.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.5, 4
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).5 + 4 = 9
- Decide. The digits add up to 9.Yes, 54 is in the 9 times table.
Check. 9 × 6 = 54. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Watch out
For the 9 times table, take away the other number, not 9. 9 × 6 is 60 − 6 = 54, not 60 − 9. For the 6 times table add one more group to the 5 times table, not six more. And for the finger trick, do not count the folded finger.Exercise 3C The 3, 6, 9 and 12 times tables
Non-calculatorMethod. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 4 = 4 × 3. Use the 4 times table trick.3 × 4 = 4 × 3
- Double the number. This gives 2 lots.3 + 3 = 6
- Double the answer again. Doubling twice gives 4 lots.6 + 6 = 12
- Write the answer. 3 × 4 = 12
Check. Check by dividing: 12 ÷ 3 = 4. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.6 + 6 = 12
- Add one more group. 3 = 2 + 1, so add the number once more.12 + 6 = 18
- Write the answer. 3 × 6 = 18
Check. Check by dividing: 18 ÷ 3 = 6. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 3 = 3 × 7. Use the 3 times table trick.7 × 3 = 3 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 7 × 3 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 9 = 9 × 3. Use the 9 times table trick.3 × 9 = 9 × 3
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Take away one group. 9 = 10 − 1, so take away the number itself once.30 − 3 = 27
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).3 × 9 = 27
Check. The digits of 27 add up to 9: 2 + 7 = 9. ✓
Watch out. Take away 3, the other number, not 9. For 9 × 3 you work out 10 × 3 − 3.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 11 = 11 × 3. Use the 11 times table trick.3 × 11 = 11 × 3
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 33.30 + 3 = 33
- Write the answer. 3 × 11 = 33
Check. Check by dividing: 33 ÷ 3 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 3 = 3 × 12. Use the 3 times table trick.12 × 3 = 3 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add one more group. 3 = 2 + 1, so add the number once more.24 + 12 = 36
- Write the answer. 12 × 3 = 36
Check. Check by dividing: 36 ÷ 3 = 12. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.8 + 8 = 16
- Add one more group. 3 = 2 + 1, so add the number once more.16 + 8 = 24
- Write the answer. 3 × 8 = 24
Check. Check by dividing: 24 ÷ 3 = 8. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 3 = 30
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 20 = 10, half of 10 = 5, so 10 + 5 = 15
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 3 = 15
Check. Check by dividing: 15 ÷ 3 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 10 = 10 × 3. Use the 10 times table trick.3 × 10 = 10 × 3
- Think about tens. 10 × 3 means 3 lots of 10, which is 3 tens.3 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.3 → 30
- Write the answer. 3 × 10 = 30
Check. Check by dividing: 30 ÷ 3 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add one more group. 3 = 2 + 1, so add the number once more.24 + 12 = 36
- Write the answer. 3 × 12 = 36
Check. Check by dividing: 36 ÷ 3 = 12. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 4 = 4 × 6. Use the 4 times table trick.6 × 4 = 4 × 6
- Double the number. This gives 2 lots.6 + 6 = 12
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 6 × 4 = 24
Check. Check by dividing: 24 ÷ 4 = 6. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 60 halved.5 × 6 = 30
- Add one more group. 6 = 5 + 1, so add the number once more.30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 6 = 6 × 7. Use the 6 times table trick.7 × 6 = 6 × 7
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 7 × 6 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 9 = 9 × 6. Use the 9 times table trick.6 × 9 = 9 × 6
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).6 × 9 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 11 = 11 × 6. Use the 11 times table trick.6 × 11 = 11 × 6
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 66.60 + 6 = 66
- Write the answer. 6 × 11 = 66
Check. Check by dividing: 66 ÷ 6 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 12 × 6 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 8 × 6 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 5 = 5 × 6. Use the 5 times table trick.6 × 5 = 5 × 6
- Multiply by 10. This is easy: move the digits one place to the left.10 × 6 = 60
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30
- Write the answer. Answers in the 5 times table end in 0 or 5.6 × 5 = 30
Check. Check by dividing: 30 ÷ 5 = 6. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 10 = 10 × 6. Use the 10 times table trick.6 × 10 = 10 × 6
- Think about tens. 10 × 6 means 6 lots of 10, which is 6 tens.6 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.6 → 60
- Write the answer. 6 × 10 = 60
Check. Check by dividing: 60 ÷ 6 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 3 = 3 × 6. Use the 3 times table trick.6 × 3 = 3 × 6
- Double the number. This gives 2 lots.6 + 6 = 12
- Add one more group. 3 = 2 + 1, so add the number once more.12 + 6 = 18
- Write the answer. 6 × 3 = 18
Check. Check by dividing: 18 ÷ 3 = 6. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Take away one group. 9 = 10 − 1, so take away the number itself once.30 − 3 = 27
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 3 = 27
Check. The digits of 27 add up to 9: 2 + 7 = 9. ✓
Watch out. Take away 3, the other number, not 9. For 9 × 3 you work out 10 × 3 − 3.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 6 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 9 = 9 × 7. Use the 9 times table trick.7 × 9 = 9 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).7 × 9 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Take away one group. 9 = 10 − 1, so take away the number itself once.90 − 9 = 81
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 9 = 81
Check. The digits of 81 add up to 9: 8 + 1 = 9. ✓
Watch out. Take away 9, the other number, not 9. For 9 × 9 you work out 10 × 9 − 9.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 11 = 11 × 9. Use the 11 times table trick.9 × 11 = 11 × 9
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 99.90 + 9 = 99
- Write the answer. 9 × 11 = 99
Check. The digits of 99 add up to 9: 9 + 9 = 18. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 9 = 9 × 12. Use the 9 times table trick.12 × 9 = 9 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Take away one group. 9 = 10 − 1, so take away the number itself once.120 − 12 = 108
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).12 × 9 = 108
Check. Check by dividing: 108 ÷ 9 = 12. ✓
Watch out. Take away 12, the other number, not 9. For 9 × 12 you work out 10 × 12 − 12.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Take away one group. 9 = 10 − 1, so take away the number itself once.80 − 8 = 72
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 8 = 72
Check. The digits of 72 add up to 9: 7 + 2 = 9. ✓
Watch out. Take away 8, the other number, not 9. For 9 × 8 you work out 10 × 8 − 8.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 9 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 10 = 10 × 9. Use the 10 times table trick.9 × 10 = 10 × 9
- Think about tens. 10 × 9 means 9 lots of 10, which is 9 tens.9 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.9 → 90
- Write the answer. 9 × 10 = 90
Check. The digits of 90 add up to 9: 9 + 0 = 9. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 4 = 4 × 9. Use the 4 times table trick.9 × 4 = 4 × 9
- Double the number. This gives 2 lots.9 + 9 = 18
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 8 = 16, so 20 + 16 = 36
- Write the answer. 9 × 4 = 36
Check. The digits of 36 add up to 9: 3 + 6 = 9. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 3 = 3 × 12. Use the 3 times table trick.12 × 3 = 3 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add one more group. 3 = 2 + 1, so add the number once more.24 + 12 = 36
- Write the answer. 12 × 3 = 36
Check. Check by dividing: 36 ÷ 3 = 12. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 12 × 6 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 12 = 12 × 7. Use the 12 times table trick.7 × 12 = 12 × 7
- Multiply by 10. Move the digits one place to the left.10 × 7 = 70
- Multiply by 2. Double the number.7 + 7 = 14
- Add the two answers together. 12 = 10 + 2.70 + 14 = 84
- Write the answer. 7 × 12 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 9 = 9 × 12. Use the 9 times table trick.12 × 9 = 9 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Take away one group. 9 = 10 − 1, so take away the number itself once.120 − 12 = 108
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).12 × 9 = 108
Check. Check by dividing: 108 ÷ 9 = 12. ✓
Watch out. Take away 12, the other number, not 9. For 9 × 12 you work out 10 × 12 − 12.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 11 = 11 × 12. Use the 11 times table trick.12 × 11 = 11 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Add one more group. 11 = 10 + 1, so add the number itself once more.120 + 12 = 132
- Write the answer. 12 × 11 = 132
Check. Check by dividing: 132 ÷ 11 = 12. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 12 = 120
- Multiply by 2. Double the number.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add the two answers together. 12 = 10 + 2.120 + 24 = 144
- Write the answer. 12 × 12 = 144
Check. Check by dividing: 144 ÷ 12 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 12 = 12 × 8. Use the 12 times table trick.8 × 12 = 12 × 8
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 8 × 12 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 4 = 4 × 12. Use the 4 times table trick.12 × 4 = 4 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 12 × 4 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 3 × 7 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 8 = 8 × 6. Use the 8 times table trick.6 × 8 = 8 × 6
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 7 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 12 × 8 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add one more group. 3 = 2 + 1, so add the number once more.24 + 12 = 36
- Write the answer. 3 × 12 = 36
Check. Check by dividing: 36 ÷ 3 = 12. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 60 halved.5 × 6 = 30
- Add one more group. 6 = 5 + 1, so add the number once more.30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 5 = 5 × 9. Use the 5 times table trick.9 × 5 = 5 × 9
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.9 × 5 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 10 = 10 × 12. Use the 10 times table trick.12 × 10 = 10 × 12
- Think about tens. 10 × 12 means 12 lots of 10, which is 12 tens.12 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.12 → 120
- Write the answer. 12 × 10 = 120
Check. Check by dividing: 120 ÷ 10 = 12. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 6 = 6 × 7. Use the 6 times table trick.7 × 6 = 6 × 7
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 7 × 6 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 99.90 + 9 = 99
- Write the answer. 11 × 9 = 99
Check. The digits of 99 add up to 9: 9 + 9 = 18. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 4 × 12 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 3 = 3 × 8. Use the 3 times table trick.8 × 3 = 3 × 8
- Double the number. This gives 2 lots.8 + 8 = 16
- Add one more group. 3 = 2 + 1, so add the number once more.16 + 8 = 24
- Write the answer. 8 × 3 = 24
Check. Check by dividing: 24 ÷ 3 = 8. ✓
Watch out. Add the number itself, not 3, as the extra group.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 3 is multiplied by to make 27.3 × ? = 27
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 27 by 3.27 ÷ 3 = 9
- Write the missing number. 3 × 9 = 27
Check. Put it back: 3 × 9 = 27. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 6, makes 48.? × 6 = 48
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 48 by 6.48 ÷ 6 = 8
- Write the missing number. 8 × 6 = 48
Check. Put it back: 8 × 6 = 48. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 9 is multiplied by to make 72.9 × ? = 72
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 72 by 9.72 ÷ 9 = 8
- Write the missing number. 9 × 8 = 72
Check. Put it back: 9 × 8 = 72. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 12, makes 96.? × 12 = 96
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 96 by 12.96 ÷ 12 = 8
- Write the missing number. 8 × 12 = 96
Check. Put it back: 8 × 12 = 96. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 6 is multiplied by to make 54.6 × ? = 54
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 54 by 6.54 ÷ 6 = 9
- Write the missing number. 6 × 9 = 54
Check. Put it back: 6 × 9 = 54. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 3, makes 33.? × 3 = 33
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 33 by 3.33 ÷ 3 = 11
- Write the missing number. 11 × 3 = 33
Check. Put it back: 11 × 3 = 33. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Hold up all ten fingers. Fold down the finger that matches the number you are multiplying 9 by. The fingers either side give the answer.
- Hold up ten fingers and number them 1 to 10. Number the fingers from left to right. Fold down finger 4.
- Count the fingers on the left of the folded finger. This is the number of tens.3 fingers on the left = 3 tens
- Count the fingers on the right of the folded finger. This is the number of ones.6 fingers on the right = 6 ones
- Write the tens and ones together. 9 × 4 = 36
Check. Use the other method: 10 × 4 = 40, then 40 − 4 = 36. ✓
Watch out. The folded finger is not counted. Count only the fingers that are still up.
Method. Hold up all ten fingers. Fold down the finger that matches the number you are multiplying 9 by. The fingers either side give the answer.
- Hold up ten fingers and number them 1 to 10. Number the fingers from left to right. Fold down finger 6.
- Count the fingers on the left of the folded finger. This is the number of tens.5 fingers on the left = 5 tens
- Count the fingers on the right of the folded finger. This is the number of ones.4 fingers on the right = 4 ones
- Write the tens and ones together. 9 × 6 = 54
Check. Use the other method: 10 × 6 = 60, then 60 − 6 = 54. ✓
Watch out. The folded finger is not counted. Count only the fingers that are still up.
Method. Hold up all ten fingers. Fold down the finger that matches the number you are multiplying 9 by. The fingers either side give the answer.
- Hold up ten fingers and number them 1 to 10. Number the fingers from left to right. Fold down finger 8.
- Count the fingers on the left of the folded finger. This is the number of tens.7 fingers on the left = 7 tens
- Count the fingers on the right of the folded finger. This is the number of ones.2 fingers on the right = 2 ones
- Write the tens and ones together. 9 × 8 = 72
Check. Use the other method: 10 × 8 = 80, then 80 − 8 = 72. ✓
Watch out. The folded finger is not counted. Count only the fingers that are still up.
Method. Hold up all ten fingers. Fold down the finger that matches the number you are multiplying 9 by. The fingers either side give the answer.
- Hold up ten fingers and number them 1 to 10. Number the fingers from left to right. Fold down finger 9.
- Count the fingers on the left of the folded finger. This is the number of tens.8 fingers on the left = 8 tens
- Count the fingers on the right of the folded finger. This is the number of ones.1 finger on the right = 1 ones
- Write the tens and ones together. 9 × 9 = 81
Check. Use the other method: 10 × 9 = 90, then 90 − 9 = 81. ✓
Watch out. The folded finger is not counted. Count only the fingers that are still up.
Method. Find the step between the numbers, then add it each time to fill the gaps.
- Find the step. Look at two numbers that are next to each other. How much bigger is the second?9 to 18: 18 − 9 = 9. We are counting in 9s.
- Fill each gap. Add 9 to the number before the gap.27 + 9 = 36
45 + 9 = 54
63 + 9 = 72 - Say the whole sequence. Read it from the start to check it sounds right.9, 18, 27, 36, 45, 54, 63, 72, 81, 90
Check. Every number is a multiple of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90. ✓
Watch out. Check each jump is the same size (9), including the jump into and out of each gap.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.4, 5
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).4 + 5 = 9
- Decide. The digits add up to 9.Yes, 45 is in the 9 times table.
Check. 9 × 5 = 45. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.5, 4
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).5 + 4 = 9
- Decide. The digits add up to 9.Yes, 54 is in the 9 times table.
Check. 9 × 6 = 54. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.6, 2
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).6 + 2 = 8
- Decide. 8 is not 9, so 62 is not in the 9 times table.No, 62 is not in the 9 times table.
Check. 9 × 6 = 54 and 9 × 7 = 63. 62 is in between. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.7, 2
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).7 + 2 = 9
- Decide. The digits add up to 9.Yes, 72 is in the 9 times table.
Check. 9 × 8 = 72. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.8, 5
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).8 + 5 = 13
- Decide. 13 is not 9, so 85 is not in the 9 times table.No, 85 is not in the 9 times table.
Check. 9 × 9 = 81 and 9 × 10 = 90. 85 is in between. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. Add up the digits. If they make 9 (or add to 9 again), the number is in the 9 times table.
- Split the number into digits. The digit test looks at each digit on its own.3, 6
- Add the digits. Every number in the 9 times table has digits that add up to 9 (or to 18, which adds to 9 again).3 + 6 = 9
- Decide. The digits add up to 9.Yes, 36 is in the 9 times table.
Check. 9 × 4 = 36. ✓
Watch out. Add the digits and look for 9. It is not enough for the digits to be big or for the number to be odd.
Method. There are 6 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 6 equal bars show 6 equal boxes. Each bar is 12. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.6 × 12
- Work it out. Use a times table trick.10 × 6 = 60
6 + 6 = 12
60 + 12 = 72
6 × 12 = 72 - Write the answer. Include the unit.72 eggs
Check. Divide back: 72 ÷ 6 = 12. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 7 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 7 equal bars show 7 equal tickets. Each bar is £9. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.7 × £9
- Work it out. Use a times table trick.10 × 7 = 70
70 − 7 = 63
7 × 9 = 63 - Write the answer. Include the unit.£63
Check. Divide back: 63 ÷ 7 = 9. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 11 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 11 equal bars show 11 equal tricycles. Each bar is 3. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.11 × 3
- Work it out. Use a times table trick.10 × 3 = 30
30 + 3 = 33
11 × 3 = 33 - Write the answer. Include the unit.33 wheels
Check. Divide back: 33 ÷ 11 = 3. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Check Aisha’s method one step at a time. 9 is one less than 10, so she should take away one group of 6.
- Check the first step. 10 lots of 6 is correct.10 × 6 = 60
- Find the mistake. Aisha took away 9. But 9 × 6 is 10 groups of 6 take away 1 group of 6. One group is 6, not 9.60 − 9 = 51 (wrong)
- Do it correctly. Take away 6.60 − 6 = 54
Check. Digits of 54: 5 + 4 = 9. ✓
Watch out. In “ten lots take away one lot”, the one lot is the other number (6), not 9.
Method. List the 6 times table and look at the last digits. Then explain why it always works.
- List the 6 times table. Count up in 6s.6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72
- Look at the ones digits. Even numbers end in 0, 2, 4, 6 or 8.The ones digits are 6, 2, 8, 4, 0, 6, 2, 8, 4, 0, 6, 2. All even.
- Explain why it always works. 6 is double 3, so 6 × any number = double (3 × that number). A double is always even.6 × 7 = 2 × (3 × 7) = 2 × 21 = 42
- Answer. Yes. Every answer is a double, so it is even.
Check. Every even number can be shared into two equal groups. 42 ÷ 2 = 21. ✓
Watch out. Listing examples is a good start, but a proof also needs a reason why it always works.
Method. Look for something that all but one of the numbers have in common. Try adding the digits.
- Add the digits of each number. Numbers in the 9 times table have digits that add up to 9.18: 1 + 8 = 9
27: 2 + 7 = 9
36: 3 + 6 = 9
40: 4 + 0 = 4
45: 4 + 5 = 9 - Choose the odd one out. 40 is the only one whose digits do not add up to 9.40. It is not in the 9 times table.
Check. 9 × 2 = 18, 9 × 3 = 27, 9 × 4 = 36, 9 × 5 = 45. But 40 is between 36 and 45. ✓
Watch out. There may be another reason too (for example, 45 is odd). Always check that your reason works for all the numbers.
Method. List the numbers between 20 and 30 in each table. Find the number that is in both.
- List the 3 times table between 20 and 30. Count up in 3s.21, 24, 27
- List the 4 times table between 20 and 30. Count up in 4s.24, 28
- Find the number in both lists. 24
Check. 3 × 8 = 24 and 4 × 6 = 24. ✓
Watch out. The number must be in both lists. 21 is only in the 3s and 28 is only in the 4s.
The 7 and 11 times tables, square numbers and the whole grid
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
The 7 times table. This is often called the hardest table, but you already know almost all of it! 7 × 2, 7 × 3, 7 × 4, 7 × 5, 7 × 9, 7 × 10 and 7 × 12 come from tricks you know. The ones to practise are 6 × 7 = 42, 7 × 7 = 49 and 7 × 8 = 56. To remember 56 = 7 × 8, notice the digits in order: 5, 6, 7, 8. If you forget a fact, build it: 7 × 7 = 5 × 7 + 2 × 7 = 35 + 14 = 49.
The 11 times table. From 11 × 1 to 11 × 9, write the digit twice: 11 × 4 = 44 and 11 × 7 = 77. After that, use ten lots and one more lot: 11 × 10 = 110, 11 × 11 = 110 + 11 = 121 and 11 × 12 = 120 + 12 = 132.
Square numbers. When you multiply a number by itself, such as 5 × 5 = 25, the dots in the array make a perfect square. 1, 4, 9, 16, 25, ... are called square numbers. The first twelve are 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121 and 144.
The whole grid. Here is the complete multiplication grid up to 12 × 12. The square numbers form a diagonal line (orange). The grid is a mirror image across this line, because 7 × 8 = 8 × 7 (blue). There are 144 facts in the grid, but because of commutativity only 78 of them are different. And you already know all of the × 0, × 1, × 2, × 5 and × 10 facts.
Key words. A square number is what you get when you multiply a whole number by itself. A grid is rows and columns of boxes.
Key ideas
- × 7: 5 lots + 2 lots. Learn 6 × 7 = 42, 7 × 7 = 49 and 7 × 8 = 56 (5, 6, 7, 8).
- × 11 (up to 11 × 9): write the digit twice. After that: × 10 and add one more lot.
- Square numbers: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144.
- There are 144 facts in the grid but only 78 different ones, because 7 × 8 = 8 × 7.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 6 × 7 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Seven is five and two. Work out 5 lots and 2 lots, then add them.
- Work out 5 lots. The 5 times table is half of the 10 times table.5 × 7 = 35
- Work out 2 lots. Double the number.7 + 7 = 14
- Add them. 7 = 5 + 2.35 + 14 = 49
- Write the answer. 7 × 7 = 49
Check. Check by dividing: 49 ÷ 7 = 7. ✓
Watch out. Do not forget the 2 lots. 7 lots = 5 lots + 2 lots.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 8 = 8 × 7. Use the 8 times table trick.7 × 8 = 8 × 7
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 7 = 70
- Multiply by 2. Double the number.7 + 7 = 14
- Add the two answers together. 12 = 10 + 2.70 + 14 = 84
- Write the answer. 12 × 7 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 66.60 + 6 = 66
- Write the answer. 11 × 6 = 66
Check. Check by dividing: 66 ÷ 6 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Add one more group. 11 = 10 + 1, so add the number itself once more.120 + 12 = 132
- Write the answer. 11 × 12 = 132
Check. Check by dividing: 132 ÷ 11 = 12. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 12 = 120
- Multiply by 2. Double the number.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add the two answers together. 12 = 10 + 2.120 + 24 = 144
- Write the answer. 12 × 12 = 144
Check. Check by dividing: 144 ÷ 12 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. A square number makes a square array: the same number of rows and columns.
- Find a pair of equal numbers that multiply to 49. Try the times tables. 7 × 7 is 49.7 × 7 = 49
- Check the array. The array has 7 rows and 7 columns. It is a square.7 rows of 7 dots
- Answer. Yes. 49 is a square number because 7 × 7 = 49.
Check. The square numbers in order: 1, 4, 9, 16, 25, 36, 49, 64. ✓
Watch out. The array must be a square. 7 × 8 = 56 is a rectangle, not a square, so 56 is not a square number.
Watch out
The “write the digit twice” trick for 11 only works up to 11 × 9. 11 × 12 is not 1212. It is 120 + 12 = 132. Also, 7 × 8 is 56, not 54 or 58. If you forget a fact, build it from ones you know, such as 5 lots and 3 lots of 7.Exercise 3D The 7 and 11 times tables, squares and the grid
Non-calculatorMethod. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 3 = 3 × 7. Use the 3 times table trick.7 × 3 = 3 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 7 × 3 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 6 = 6 × 7. Use the 6 times table trick.7 × 6 = 6 × 7
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 7 × 6 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Seven is five and two. Work out 5 lots and 2 lots, then add them.
- Work out 5 lots. The 5 times table is half of the 10 times table.5 × 7 = 35
- Work out 2 lots. Double the number.7 + 7 = 14
- Add them. 7 = 5 + 2.35 + 14 = 49
- Write the answer. 7 × 7 = 49
Check. Check by dividing: 49 ÷ 7 = 7. ✓
Watch out. Do not forget the 2 lots. 7 lots = 5 lots + 2 lots.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 8 = 8 × 7. Use the 8 times table trick.7 × 8 = 8 × 7
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 7 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 11 = 11 × 7. Use the 11 times table trick.7 × 11 = 11 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 77.70 + 7 = 77
- Write the answer. 7 × 11 = 77
Check. Check by dividing: 77 ÷ 7 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 7 = 70
- Multiply by 2. Double the number.7 + 7 = 14
- Add the two answers together. 12 = 10 + 2.70 + 14 = 84
- Write the answer. 12 × 7 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 4 = 4 × 7. Use the 4 times table trick.7 × 4 = 4 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Write the answer. 7 × 4 = 28
Check. Check by dividing: 28 ÷ 4 = 7. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 7 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 7 means 7 lots of 10, which is 7 tens.7 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.7 → 70
- Write the answer. 10 × 7 = 70
Check. Check by dividing: 70 ÷ 7 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 2 = 2 × 11. Use the 2 times table trick.11 × 2 = 2 × 11
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 1 = 2, so 20 + 2 = 22
- Write the answer. 11 × 2 = 22
Check. Check by dividing: 22 ÷ 2 = 11. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 5 = 5 × 11. Use the 5 times table trick.11 × 5 = 5 × 11
- Multiply by 10. This is easy: move the digits one place to the left.10 × 11 = 110
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 100 = 50, half of 10 = 5, so 50 + 5 = 55
- Write the answer. Answers in the 5 times table end in 0 or 5.11 × 5 = 55
Check. Check by dividing: 55 ÷ 5 = 11. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 99.90 + 9 = 99
- Write the answer. 11 × 9 = 99
Check. The digits of 99 add up to 9: 9 + 9 = 18. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 11 = 11 × 3. Use the 11 times table trick.3 × 11 = 11 × 3
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 33.30 + 3 = 33
- Write the answer. 3 × 11 = 33
Check. Check by dividing: 33 ÷ 3 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 10 = 10 × 11. Use the 10 times table trick.11 × 10 = 10 × 11
- Think about tens. 10 × 11 means 11 lots of 10, which is 11 tens.11 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.11 → 110
- Write the answer. 11 × 10 = 110
Check. Check by dividing: 110 ÷ 10 = 11. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 11 = 110
- Add one more group. 11 = 10 + 1, so add the number itself once more.110 + 11 = 121
- Write the answer. 11 × 11 = 121
Check. Check by dividing: 121 ÷ 11 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 11 = 11 × 12. Use the 11 times table trick.12 × 11 = 11 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Add one more group. 11 = 10 + 1, so add the number itself once more.120 + 12 = 132
- Write the answer. 12 × 11 = 132
Check. Check by dividing: 132 ÷ 11 = 12. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 11 = 11 × 7. Use the 11 times table trick.7 × 11 = 11 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 77.70 + 7 = 77
- Write the answer. 7 × 11 = 77
Check. Check by dividing: 77 ÷ 7 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 88.80 + 8 = 88
- Write the answer. 11 × 8 = 88
Check. Check by dividing: 88 ÷ 8 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 11 = 11 × 4. Use the 11 times table trick.4 × 11 = 11 × 4
- Multiply by 10. 10 lots of the number first.10 × 4 = 40
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 44.40 + 4 = 44
- Write the answer. 4 × 11 = 44
Check. Check by dividing: 44 ÷ 4 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.3 + 3 = 6
- Add one more group. 3 = 2 + 1, so add the number once more.6 + 3 = 9
- Write the answer. 3 × 3 = 9
Check. Check by dividing: 9 ÷ 3 = 3. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 5 = 50
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20, half of 10 = 5, so 20 + 5 = 25
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 5 = 25
Check. Check by dividing: 25 ÷ 5 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 60 halved.5 × 6 = 30
- Add one more group. 6 = 5 + 1, so add the number once more.30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.8 + 8 = 16
- Double again. This gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Double a third time. This gives 8 lots.double 30 = 60, double 2 = 4, so 60 + 4 = 64
- Write the answer. 8 × 8 = 64
Check. Check by dividing: 64 ÷ 8 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Take away one group. 9 = 10 − 1, so take away the number itself once.90 − 9 = 81
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 9 = 81
Check. The digits of 81 add up to 9: 8 + 1 = 9. ✓
Watch out. Take away 9, the other number, not 9. For 9 × 9 you work out 10 × 9 − 9.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 10 means 10 lots of 10, which is 10 tens.10 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.10 → 100
- Write the answer. 10 × 10 = 100
Check. Check by dividing: 100 ÷ 10 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 11 = 110
- Add one more group. 11 = 10 + 1, so add the number itself once more.110 + 11 = 121
- Write the answer. 11 × 11 = 121
Check. Check by dividing: 121 ÷ 11 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 12 = 120
- Multiply by 2. Double the number.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add the two answers together. 12 = 10 + 2.120 + 24 = 144
- Write the answer. 12 × 12 = 144
Check. Check by dividing: 144 ÷ 12 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 60 halved.5 × 6 = 30
- Add one more group. 6 = 5 + 1, so add the number once more.30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 6 × 7 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 8 = 8 × 6. Use the 8 times table trick.6 × 8 = 8 × 6
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Seven is five and two. Work out 5 lots and 2 lots, then add them.
- Work out 5 lots. The 5 times table is half of the 10 times table.5 × 7 = 35
- Work out 2 lots. Double the number.7 + 7 = 14
- Add them. 7 = 5 + 2.35 + 14 = 49
- Write the answer. 7 × 7 = 49
Check. Check by dividing: 49 ÷ 7 = 7. ✓
Watch out. Do not forget the 2 lots. 7 lots = 5 lots + 2 lots.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 8 = 8 × 7. Use the 8 times table trick.7 × 8 = 8 × 7
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.8 + 8 = 16
- Double again. This gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Double a third time. This gives 8 lots.double 30 = 60, double 2 = 4, so 60 + 4 = 64
- Write the answer. 8 × 8 = 64
Check. Check by dividing: 64 ÷ 8 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 9 = 9 × 6. Use the 9 times table trick.6 × 9 = 9 × 6
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).6 × 9 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 9 = 9 × 7. Use the 9 times table trick.7 × 9 = 9 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).7 × 9 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 9 = 9 × 8. Use the 9 times table trick.8 × 9 = 9 × 8
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Take away one group. 9 = 10 − 1, so take away the number itself once.80 − 8 = 72
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).8 × 9 = 72
Check. The digits of 72 add up to 9: 7 + 2 = 9. ✓
Watch out. Take away 8, the other number, not 9. For 9 × 8 you work out 10 × 8 − 8.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Take away one group. 9 = 10 − 1, so take away the number itself once.90 − 9 = 81
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 9 = 81
Check. The digits of 81 add up to 9: 8 + 1 = 9. ✓
Watch out. Take away 9, the other number, not 9. For 9 × 9 you work out 10 × 9 − 9.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 12 = 12 × 6. Use the 12 times table trick.6 × 12 = 12 × 6
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 6 × 12 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 12 = 12 × 8. Use the 12 times table trick.8 × 12 = 12 × 8
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 8 × 12 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 7 is multiplied by to make 63.7 × ? = 63
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 63 by 7.63 ÷ 7 = 9
- Write the missing number. 7 × 9 = 63
Check. Put it back: 7 × 9 = 63. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 11, makes 88.? × 11 = 88
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 88 by 11.88 ÷ 11 = 8
- Write the missing number. 8 × 11 = 88
Check. Put it back: 8 × 11 = 88. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 8 is multiplied by to make 56.8 × ? = 56
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 56 by 8.56 ÷ 8 = 7
- Write the missing number. 8 × 7 = 56
Check. Put it back: 8 × 7 = 56. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 7, makes 84.? × 7 = 84
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 84 by 7.84 ÷ 7 = 12
- Write the missing number. 12 × 7 = 84
Check. Put it back: 12 × 7 = 84. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 12 is multiplied by to make 144.12 × ? = 144
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 144 by 12.144 ÷ 12 = 12
- Write the missing number. 12 × 12 = 144
Check. Put it back: 12 × 12 = 144. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 9, makes 81.? × 9 = 81
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 81 by 9.81 ÷ 9 = 9
- Write the missing number. 9 × 9 = 81
Check. Put it back: 9 × 9 = 81. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 8 = 8 × 6. Use the 8 times table trick.6 × 8 = 8 × 6
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Seven is five and two. Work out 5 lots and 2 lots, then add them.
- Work out 5 lots. The 5 times table is half of the 10 times table.5 × 7 = 35
- Work out 2 lots. Double the number.7 + 7 = 14
- Add them. 7 = 5 + 2.35 + 14 = 49
- Write the answer. 7 × 7 = 49
Check. Check by dividing: 49 ÷ 7 = 7. ✓
Watch out. Do not forget the 2 lots. 7 lots = 5 lots + 2 lots.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 9 = 9 × 7. Use the 9 times table trick.7 × 9 = 9 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).7 × 9 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 9 = 9 × 8. Use the 9 times table trick.8 × 9 = 9 × 8
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Take away one group. 9 = 10 − 1, so take away the number itself once.80 − 8 = 72
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).8 × 9 = 72
Check. The digits of 72 add up to 9: 7 + 2 = 9. ✓
Watch out. Take away 8, the other number, not 9. For 9 × 8 you work out 10 × 8 − 8.
Method. Square numbers are made by multiplying a number by itself. Try the numbers in order until you go past 100.
- Start with numbers that are too small. 5 × 5 = 25 is less than 30.5 × 5 = 25 (too small)
- Try the next numbers. Keep going until the answer is more than 100.6 × 6 = 36 7 × 7 = 49 8 × 8 = 64 9 × 9 = 81 10 × 10 = 100
- Choose the ones between 30 and 100. 100 is not between 30 and 100.36, 49, 64, 81
Check. Look at the diagonal of the grid: 25, 36, 49, 64, 81, 100. ✓
Watch out. “Between 30 and 100” does not include 100.
Method. There are 8 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 8 equal bars show 8 equal weeks. Each bar is 7. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.8 × 7
- Work it out. Use a times table trick.7 + 7 = 14
double 10 = 20, double 4 = 8, so 20 + 8 = 28
double 20 = 40, double 8 = 16, so 40 + 16 = 56
8 × 7 = 56 - Write the answer. Include the unit.56 days
Check. Divide back: 56 ÷ 8 = 7. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 9 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 9 equal bars show 9 equal teams. Each bar is 11. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.9 × 11
- Work it out. Use a times table trick.10 × 9 = 90
90 + 9 = 99
9 × 11 = 99 - Write the answer. Include the unit.99 players
Check. Divide back: 99 ÷ 9 = 11. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. The plants are in an array of 9 rows with 9 in each row, so multiply 9 × 9.
- Count the rows and columns. There are 9 rows and 9 plants in each row.9 rows of 9
- Multiply. Use the 9 times table: ten lots take away one lot.10 × 9 = 90
90 − 9 = 81
9 × 9 = 81 - Write the answer. The garden is a square, so 81 is a square number.81 plants
Check. The digits of 81 add up to 9: 8 + 1 = 9. ✓
Watch out. Rows and columns means multiply. Do not add 9 + 9.
Method. There are 6 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 6 equal bars show 6 equal pizzas. Each bar is £7. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.6 × £7
- Work it out. Use a times table trick.5 × 7 = 35
35 + 7 = 42
6 × 7 = 42 - Write the answer. Include the unit.£42
Check. Divide back: 42 ÷ 6 = 7. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Check Ravi’s answer by building 7 × 8 from facts you know.
- Use 7 × 7 = 49. 7 × 8 is one more group of 7 than 7 × 7.7 × 7 = 49
- Add one more group of 7. 49 + 7 = 56
- Compare with Ravi. Ravi said 54. The digits in order are 5, 6, 7, 8, so the fact is 56 = 7 × 8.56, not 54
Check. Also 5 × 8 = 40 and 2 × 8 = 16, and 40 + 16 = 56. ✓
Watch out. Learn 7 × 8 = 56 by the pattern 5, 6, 7, 8.
Method. Try all the numbers from 1 to 9.
- Write the facts. 11 times a digit gives the digit twice.11, 22, 33, 44, 55, 66, 77, 88, 99
- Decide. Every answer has two matching digits.Always
Check. 11 × 9 = 99. ✓
Watch out. Be careful: it stops working after 11 × 9. 11 × 10 = 110.
Method. Look at some square numbers.
- List some. Some end in an even digit and some in an odd digit.4, 16, 36, 64 are even. 9, 25, 49, 81 are odd.
- Decide. We found some of each.Sometimes
Check. Even × even is even (4 × 4 = 16) and odd × odd is odd (5 × 5 = 25). ✓
Watch out. “Sometimes” needs an example that works and an example that does not.
Method. Look for a property that three numbers share. Try writing each number as a multiplication.
- Write each as a multiplication fact. See if any of them is a number times itself.49 = 7 × 7
64 = 8 × 8
56 = 7 × 8
81 = 9 × 9 - Choose the odd one out. 49, 64 and 81 are square numbers. 56 is 7 × 8, which is not a number times itself.56
Check. The square numbers are on the diagonal of the grid. 56 is not on it. ✓
Watch out. 56 can also be 4 × 14 or 2 × 28, but none of those have equal numbers.
Method. The grid is a mirror image across the diagonal. Count the boxes on one side of the diagonal, including the diagonal.
- Look at the picture. The shaded boxes are the diagonal and everything above it. Every other box is a mirror copy of a shaded box.Count the shaded boxes row by row.
- Count row by row. Row 1 has 12 shaded boxes, row 2 has 11, and each row has one fewer than the row before.12 + 11 + 10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1
- Add them up. Add in pairs: 12 + 1 = 13, 11 + 2 = 13, and so on. There are 6 pairs.6 × 13 = 78
- Write the answer. 78 different facts
Check. 144 − 12 = 132 boxes that are not on the diagonal. Half of 132 is 66. 66 + 12 = 78. ✓
Watch out. Do not count the diagonal twice. The square numbers (like 7 × 7) have no mirror partner.
Division facts, fact families and missing numbers
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
Division is the inverse (opposite) of multiplication. It has two meanings. Sharing: 12 sweets are shared equally between 3 children, so each child gets 12 ÷ 3 = 4. Grouping: 12 sweets are put into bags of 3, so there are 12 ÷ 3 = 4 bags. Both are the same calculation.
The best way to divide is to use the times tables. To work out 56 ÷ 7, think: 7 times what is 56? You know 7 × 8 = 56, so 56 ÷ 7 = 8. The tricks work backwards too: to divide by 2 halve, to divide by 4 halve twice, to divide by 8 halve three times, to divide by 10 move the digits one place to the right.
Fact families. Three numbers can make four facts. The array below has 4 rows and 6 columns, so it shows 4 × 6 = 24 and 6 × 4 = 24. If you split the 24 dots into 4 equal rows you get 6 in each row, so 24 ÷ 4 = 6. If you split them into 6 equal columns you get 4, so 24 ÷ 6 = 4. In the fact triangle, the product is always at the top.
Special cases. Any number divided by 1 stays the same: 9 ÷ 1 = 9. Any number divided by itself is 1: 9 ÷ 9 = 1. 0 divided by any number is 0: 0 ÷ 6 = 0. But you can never divide by 0. There is no answer to 6 ÷ 0.
Missing number problems. Use the inverse. For ? ÷ 6 = 7, the opposite of dividing by 6 is multiplying by 6, so ? = 7 × 6 = 42. For 54 ÷ ? = 6, ask: how many 6s make 54? That is 54 ÷ 6 = 9.
Key words. The inverse of a calculation undoes it. A fact family is the multiplication and division facts that use the same three numbers.
Key ideas
- Division is the inverse of multiplication: if 7 × 8 = 56 then 56 ÷ 7 = 8.
- To work out 56 ÷ 7, ask “7 times what is 56?”
- Three numbers make a fact family: 2 multiplication facts and 2 division facts.
- A number ÷ 1 is the same number. A number ÷ itself is 1. 0 ÷ a number is 0.
- You can never divide by 0.
- Missing numbers: use the opposite operation.
Method. Use the 7 times table. Count up in 7s until you reach 56.
- Turn the division into a missing multiplication. 56 ÷ 7 asks: what do we multiply 7 by to get 56?56 ÷ 7 = ? means ? × 7 = 56
- Count up in 7s until you reach 56. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49, 56
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 7 = 56
- Write the answer. 56 ÷ 7 = 8
Check. Multiply back: 8 × 7 = 56. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. Dividing by 8 is halving three times.
- Turn the division into a missing multiplication. 96 ÷ 8 asks: what do we multiply 8 by to get 96?96 ÷ 8 = ? means ? × 8 = 96
- Halve the number. 8 = 2 × 2 × 2, so we halve three times.half of 80 = 40, half of 16 = 8, so 40 + 8 = 48
- Halve again. half of 40 = 20, half of 8 = 4, so 20 + 4 = 24
- Halve a third time. half of 20 = 10, half of 4 = 2, so 10 + 2 = 12
- Write the answer. 96 ÷ 8 = 12
Check. Multiply back: 12 × 8 = 96. ✓
Watch out. Count your halves. Three halves divide by 8.
Method. Use the 11 times table. Count up in 11s until you reach 132.
- Turn the division into a missing multiplication. 132 ÷ 11 asks: what do we multiply 11 by to get 132?132 ÷ 11 = ? means ? × 11 = 132
- Count up in 11s until you reach 132. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 11 = 132
- Write the answer. 132 ÷ 11 = 12
Check. Multiply back: 12 × 11 = 132. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. To divide by 5, double the number first and then divide by 10.
- Turn the division into a missing multiplication. 35 ÷ 5 asks: what do we multiply 5 by to get 35?35 ÷ 5 = ? means ? × 5 = 35
- Double the number. Doubling then dividing by 10 is the same as dividing by 5.double 30 = 60, double 5 = 10, so 60 + 10 = 70
- Divide by 10. Move the digits one place to the right.70 ÷ 10 = 7
- Write the answer. 35 ÷ 5 = 7
Check. Multiply back: 7 × 5 = 35. ✓
Watch out. Remember to do both steps: double, then divide by 10.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Two multiplication facts and two division facts use the same three numbers.
- Put the numbers in a fact triangle. The product goes at the top and the two factors at the bottom.
- Write the two multiplication facts. Multiply the bottom numbers in either order.6 × 8 = 48
8 × 6 = 48 - Write the two division facts. Start at the top and divide by one factor to get the other.48 ÷ 6 = 8
48 ÷ 8 = 6
Check. Check one fact: 6 × 8 = 48, so 48 ÷ 8 = 6. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Both factors are 7, so there are only two facts.
- Put the numbers in a fact triangle. The product goes at the top and the factors at the bottom.
- Write the multiplication fact. Multiply the two numbers at the bottom to get the top.7 × 7 = 49
- Write the division fact. Start at the top and divide by the factor.49 ÷ 7 = 7
Check. Check one fact: 7 × 7 = 49, so 49 ÷ 7 = 7. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Method. Dividing by 1 does not change the number. Sharing between 1 person leaves everything with that person.
- Say what the division means. 9 ÷ 1 means: share 9 into 1 equal group.1 group gets all 9
- Think of a small example. Imagine sharing sweets with just one person.6 sweets shared with 1 person: they get all 6, so 6 ÷ 1 = 6
- Write the answer. One group means no sharing happens.9 ÷ 1 = 9
Check. Multiply back: 9 × 1 = 9. ✓
Watch out. Dividing by 1 does not give 1. It gives the same number.
Method. Any number divided by itself is 1. There is exactly one group of that size.
- Say what the division means. 9 ÷ 9 asks: how many groups of 9 fit into 9?one group of 9 fits
- Think of a small example. Imagine putting sweets into bags that each hold the whole amount.6 sweets in bags of 6: you fill 1 bag, so 6 ÷ 6 = 1
- Write the answer. 9 ÷ 9 = 1
Check. Multiply back: 1 × 9 = 9. ✓
Watch out. The answer is 1, not 9 and not 0.
Method. Zero shared between any number of groups is 0. There is nothing to share.
- Say what the division means. 0 ÷ 6 means: share 0 things between 6 groups.nothing to share
- Think of a small example. Imagine sharing an empty bag of sweets between 3 children.0 sweets shared between 3 children: each gets 0, so 0 ÷ 3 = 0
- Write the answer. Every group gets nothing.0 ÷ 6 = 0
Check. Multiply back: 0 × 6 = 0. ✓
Watch out. 0 ÷ 5 is 0. But you can never divide by 0: 5 ÷ 0 has no answer.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 6 gives 7.? ÷ 6 = 7
- Use the inverse (opposite) operation. The opposite of dividing by 6 is multiplying by 6.7 × 6 = 42
- Write the missing number. 42 ÷ 6 = 7
Check. Put it back: 42 ÷ 6 = 7. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 54 divided by the missing number makes 6.54 ÷ ? = 6
- Turn it into a multiplication. 6 lots of the missing number make 54.6 × ? = 54, so ? = 54 ÷ 6
- Work out the division. Count up in 6s, or use the 6 times table.54 ÷ 6 = 9
- Write the missing number. 54 ÷ 9 = 6
Check. Put it back: 54 ÷ 9 = 6. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Watch out
Division is not commutative: 56 ÷ 7 = 8, but 7 ÷ 56 is not 8. The biggest number always comes first in a division fact. And do not mix up the special cases: 9 ÷ 1 is 9 (not 1), and 9 ÷ 9 is 1 (not 9 or 0).Exercise 3E Division facts, fact families and missing numbers
Non-calculatorMethod. Dividing by 2 is halving. Find half of the number.
- Turn the division into a missing multiplication. 18 ÷ 2 asks: what do we multiply 2 by to get 18?18 ÷ 2 = ? means ? × 2 = 18
- Halve the number. Half and double are opposites.half of 18 = 9
- Write the answer. 18 ÷ 2 = 9
Check. Multiply back: 9 × 2 = 18. ✓
Watch out. Dividing by 2 is not the same as dividing into 2 digits. Half of 16 is 8.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 70 ÷ 10 asks: what do we multiply 10 by to get 70?70 ÷ 10 = ? means ? × 10 = 70
- Move the digits one place to the right. Tens become ones.70 → 7
- Write the answer. 70 ÷ 10 = 7
Check. Multiply back: 7 × 10 = 70. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Method. To divide by 5, double the number first and then divide by 10.
- Turn the division into a missing multiplication. 45 ÷ 5 asks: what do we multiply 5 by to get 45?45 ÷ 5 = ? means ? × 5 = 45
- Double the number. Doubling then dividing by 10 is the same as dividing by 5.double 40 = 80, double 5 = 10, so 80 + 10 = 90
- Divide by 10. Move the digits one place to the right.90 ÷ 10 = 9
- Write the answer. 45 ÷ 5 = 9
Check. Multiply back: 9 × 5 = 45. ✓
Watch out. Remember to do both steps: double, then divide by 10.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 120 ÷ 10 asks: what do we multiply 10 by to get 120?120 ÷ 10 = ? means ? × 10 = 120
- Move the digits one place to the right. Tens become ones.120 → 12
- Write the answer. 120 ÷ 10 = 12
Check. Multiply back: 12 × 10 = 120. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Method. To divide by 5, double the number first and then divide by 10.
- Turn the division into a missing multiplication. 50 ÷ 5 asks: what do we multiply 5 by to get 50?50 ÷ 5 = ? means ? × 5 = 50
- Double the number. Doubling then dividing by 10 is the same as dividing by 5.double 50 = 100
- Divide by 10. Move the digits one place to the right.100 ÷ 10 = 10
- Write the answer. 50 ÷ 5 = 10
Check. Multiply back: 10 × 5 = 50. ✓
Watch out. Remember to do both steps: double, then divide by 10.
Method. Dividing by 2 is halving. Find half of the number.
- Turn the division into a missing multiplication. 24 ÷ 2 asks: what do we multiply 2 by to get 24?24 ÷ 2 = ? means ? × 2 = 24
- Halve the number. Half and double are opposites.half of 20 = 10, half of 4 = 2, so 10 + 2 = 12
- Write the answer. 24 ÷ 2 = 12
Check. Multiply back: 12 × 2 = 24. ✓
Watch out. Dividing by 2 is not the same as dividing into 2 digits. Half of 16 is 8.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 110 ÷ 10 asks: what do we multiply 10 by to get 110?110 ÷ 10 = ? means ? × 10 = 110
- Move the digits one place to the right. Tens become ones.110 → 11
- Write the answer. 110 ÷ 10 = 11
Check. Multiply back: 11 × 10 = 110. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Method. To divide by 5, double the number first and then divide by 10.
- Turn the division into a missing multiplication. 60 ÷ 5 asks: what do we multiply 5 by to get 60?60 ÷ 5 = ? means ? × 5 = 60
- Double the number. Doubling then dividing by 10 is the same as dividing by 5.double 60 = 120
- Divide by 10. Move the digits one place to the right.120 ÷ 10 = 12
- Write the answer. 60 ÷ 5 = 12
Check. Multiply back: 12 × 5 = 60. ✓
Watch out. Remember to do both steps: double, then divide by 10.
Method. Dividing by 2 is halving. Find half of the number.
- Turn the division into a missing multiplication. 16 ÷ 2 asks: what do we multiply 2 by to get 16?16 ÷ 2 = ? means ? × 2 = 16
- Halve the number. Half and double are opposites.half of 16 = 8
- Write the answer. 16 ÷ 2 = 8
Check. Multiply back: 8 × 2 = 16. ✓
Watch out. Dividing by 2 is not the same as dividing into 2 digits. Half of 16 is 8.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 100 ÷ 10 asks: what do we multiply 10 by to get 100?100 ÷ 10 = ? means ? × 10 = 100
- Move the digits one place to the right. Tens become ones.100 → 10
- Write the answer. 100 ÷ 10 = 10
Check. Multiply back: 10 × 10 = 100. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Method. Use the 3 times table. Count up in 3s until you reach 21.
- Turn the division into a missing multiplication. 21 ÷ 3 asks: what do we multiply 3 by to get 21?21 ÷ 3 = ? means ? × 3 = 21
- Count up in 3s until you reach 21. Each number you say is one more group of 3.3, 6, 9, 12, 15, 18, 21
- Count how many numbers you said. The number of jumps is the answer.I said 7 numbers, so 7 × 3 = 21
- Write the answer. 21 ÷ 3 = 7
Check. Multiply back: 7 × 3 = 21. ✓
Watch out. Know your 3 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 36 ÷ 4 asks: what do we multiply 4 by to get 36?36 ÷ 4 = ? means ? × 4 = 36
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 20 = 10, half of 16 = 8, so 10 + 8 = 18
- Halve again. half of 18 = 9
- Write the answer. 36 ÷ 4 = 9
Check. Multiply back: 9 × 4 = 36. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 3 times table. Count up in 3s until you reach 27.
- Turn the division into a missing multiplication. 27 ÷ 3 asks: what do we multiply 3 by to get 27?27 ÷ 3 = ? means ? × 3 = 27
- Count up in 3s until you reach 27. Each number you say is one more group of 3.3, 6, 9, 12, 15, 18, 21, 24, 27
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 3 = 27
- Write the answer. 27 ÷ 3 = 9
Check. Multiply back: 9 × 3 = 27. ✓
Watch out. Know your 3 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 48 ÷ 4 asks: what do we multiply 4 by to get 48?48 ÷ 4 = ? means ? × 4 = 48
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 40 = 20, half of 8 = 4, so 20 + 4 = 24
- Halve again. half of 20 = 10, half of 4 = 2, so 10 + 2 = 12
- Write the answer. 48 ÷ 4 = 12
Check. Multiply back: 12 × 4 = 48. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 3 times table. Count up in 3s until you reach 33.
- Turn the division into a missing multiplication. 33 ÷ 3 asks: what do we multiply 3 by to get 33?33 ÷ 3 = ? means ? × 3 = 33
- Count up in 3s until you reach 33. Each number you say is one more group of 3.3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33
- Count how many numbers you said. The number of jumps is the answer.I said 11 numbers, so 11 × 3 = 33
- Write the answer. 33 ÷ 3 = 11
Check. Multiply back: 11 × 3 = 33. ✓
Watch out. Know your 3 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 32 ÷ 4 asks: what do we multiply 4 by to get 32?32 ÷ 4 = ? means ? × 4 = 32
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 20 = 10, half of 12 = 6, so 10 + 6 = 16
- Halve again. half of 16 = 8
- Write the answer. 32 ÷ 4 = 8
Check. Multiply back: 8 × 4 = 32. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 3 times table. Count up in 3s until you reach 36.
- Turn the division into a missing multiplication. 36 ÷ 3 asks: what do we multiply 3 by to get 36?36 ÷ 3 = ? means ? × 3 = 36
- Count up in 3s until you reach 36. Each number you say is one more group of 3.3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 3 = 36
- Write the answer. 36 ÷ 3 = 12
Check. Multiply back: 12 × 3 = 36. ✓
Watch out. Know your 3 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 44 ÷ 4 asks: what do we multiply 4 by to get 44?44 ÷ 4 = ? means ? × 4 = 44
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 40 = 20, half of 4 = 2, so 20 + 2 = 22
- Halve again. half of 20 = 10, half of 2 = 1, so 10 + 1 = 11
- Write the answer. 44 ÷ 4 = 11
Check. Multiply back: 11 × 4 = 44. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 3 times table. Count up in 3s until you reach 15.
- Turn the division into a missing multiplication. 15 ÷ 3 asks: what do we multiply 3 by to get 15?15 ÷ 3 = ? means ? × 3 = 15
- Count up in 3s until you reach 15. Each number you say is one more group of 3.3, 6, 9, 12, 15
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 3 = 15
- Write the answer. 15 ÷ 3 = 5
Check. Multiply back: 5 × 3 = 15. ✓
Watch out. Know your 3 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 40 ÷ 4 asks: what do we multiply 4 by to get 40?40 ÷ 4 = ? means ? × 4 = 40
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 40 = 20
- Halve again. half of 20 = 10
- Write the answer. 40 ÷ 4 = 10
Check. Multiply back: 10 × 4 = 40. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 6 times table. Count up in 6s until you reach 42.
- Turn the division into a missing multiplication. 42 ÷ 6 asks: what do we multiply 6 by to get 42?42 ÷ 6 = ? means ? × 6 = 42
- Count up in 6s until you reach 42. Each number you say is one more group of 6.6, 12, 18, 24, 30, 36, 42
- Count how many numbers you said. The number of jumps is the answer.I said 7 numbers, so 7 × 6 = 42
- Write the answer. 42 ÷ 6 = 7
Check. Multiply back: 7 × 6 = 42. ✓
Watch out. Know your 6 times table facts, then division is quick.
Method. Use the 7 times table. Count up in 7s until you reach 56.
- Turn the division into a missing multiplication. 56 ÷ 7 asks: what do we multiply 7 by to get 56?56 ÷ 7 = ? means ? × 7 = 56
- Count up in 7s until you reach 56. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49, 56
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 7 = 56
- Write the answer. 56 ÷ 7 = 8
Check. Multiply back: 8 × 7 = 56. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. Dividing by 8 is halving three times.
- Turn the division into a missing multiplication. 72 ÷ 8 asks: what do we multiply 8 by to get 72?72 ÷ 8 = ? means ? × 8 = 72
- Halve the number. 8 = 2 × 2 × 2, so we halve three times.half of 60 = 30, half of 12 = 6, so 30 + 6 = 36
- Halve again. half of 20 = 10, half of 16 = 8, so 10 + 8 = 18
- Halve a third time. half of 18 = 9
- Write the answer. 72 ÷ 8 = 9
Check. Multiply back: 9 × 8 = 72. ✓
Watch out. Count your halves. Three halves divide by 8.
Method. Use the 9 times table. Count up in 9s until you reach 81.
- Turn the division into a missing multiplication. 81 ÷ 9 asks: what do we multiply 9 by to get 81?81 ÷ 9 = ? means ? × 9 = 81
- Count up in 9s until you reach 81. Each number you say is one more group of 9.9, 18, 27, 36, 45, 54, 63, 72, 81
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 9 = 81
- Write the answer. 81 ÷ 9 = 9
Check. Multiply back: 9 × 9 = 81. ✓
Watch out. Know your 9 times table facts, then division is quick.
Method. Use the 6 times table. Count up in 6s until you reach 54.
- Turn the division into a missing multiplication. 54 ÷ 6 asks: what do we multiply 6 by to get 54?54 ÷ 6 = ? means ? × 6 = 54
- Count up in 6s until you reach 54. Each number you say is one more group of 6.6, 12, 18, 24, 30, 36, 42, 48, 54
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 6 = 54
- Write the answer. 54 ÷ 6 = 9
Check. Multiply back: 9 × 6 = 54. ✓
Watch out. Know your 6 times table facts, then division is quick.
Method. Use the 7 times table. Count up in 7s until you reach 63.
- Turn the division into a missing multiplication. 63 ÷ 7 asks: what do we multiply 7 by to get 63?63 ÷ 7 = ? means ? × 7 = 63
- Count up in 7s until you reach 63. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49, 56, 63
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 7 = 63
- Write the answer. 63 ÷ 7 = 9
Check. Multiply back: 9 × 7 = 63. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. Dividing by 8 is halving three times.
- Turn the division into a missing multiplication. 64 ÷ 8 asks: what do we multiply 8 by to get 64?64 ÷ 8 = ? means ? × 8 = 64
- Halve the number. 8 = 2 × 2 × 2, so we halve three times.half of 60 = 30, half of 4 = 2, so 30 + 2 = 32
- Halve again. half of 20 = 10, half of 12 = 6, so 10 + 6 = 16
- Halve a third time. half of 16 = 8
- Write the answer. 64 ÷ 8 = 8
Check. Multiply back: 8 × 8 = 64. ✓
Watch out. Count your halves. Three halves divide by 8.
Method. Use the 9 times table. Count up in 9s until you reach 108.
- Turn the division into a missing multiplication. 108 ÷ 9 asks: what do we multiply 9 by to get 108?108 ÷ 9 = ? means ? × 9 = 108
- Count up in 9s until you reach 108. Each number you say is one more group of 9.9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 9 = 108
- Write the answer. 108 ÷ 9 = 12
Check. Multiply back: 12 × 9 = 108. ✓
Watch out. Know your 9 times table facts, then division is quick.
Method. Use the 7 times table. Count up in 7s until you reach 84.
- Turn the division into a missing multiplication. 84 ÷ 7 asks: what do we multiply 7 by to get 84?84 ÷ 7 = ? means ? × 7 = 84
- Count up in 7s until you reach 84. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 7 = 84
- Write the answer. 84 ÷ 7 = 12
Check. Multiply back: 12 × 7 = 84. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. Dividing by 8 is halving three times.
- Turn the division into a missing multiplication. 96 ÷ 8 asks: what do we multiply 8 by to get 96?96 ÷ 8 = ? means ? × 8 = 96
- Halve the number. 8 = 2 × 2 × 2, so we halve three times.half of 80 = 40, half of 16 = 8, so 40 + 8 = 48
- Halve again. half of 40 = 20, half of 8 = 4, so 20 + 4 = 24
- Halve a third time. half of 20 = 10, half of 4 = 2, so 10 + 2 = 12
- Write the answer. 96 ÷ 8 = 12
Check. Multiply back: 12 × 8 = 96. ✓
Watch out. Count your halves. Three halves divide by 8.
Method. Use the 6 times table. Count up in 6s until you reach 72.
- Turn the division into a missing multiplication. 72 ÷ 6 asks: what do we multiply 6 by to get 72?72 ÷ 6 = ? means ? × 6 = 72
- Count up in 6s until you reach 72. Each number you say is one more group of 6.6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 6 = 72
- Write the answer. 72 ÷ 6 = 12
Check. Multiply back: 12 × 6 = 72. ✓
Watch out. Know your 6 times table facts, then division is quick.
Method. Use the 9 times table. Count up in 9s until you reach 90.
- Turn the division into a missing multiplication. 90 ÷ 9 asks: what do we multiply 9 by to get 90?90 ÷ 9 = ? means ? × 9 = 90
- Count up in 9s until you reach 90. Each number you say is one more group of 9.9, 18, 27, 36, 45, 54, 63, 72, 81, 90
- Count how many numbers you said. The number of jumps is the answer.I said 10 numbers, so 10 × 9 = 90
- Write the answer. 90 ÷ 9 = 10
Check. Multiply back: 10 × 9 = 90. ✓
Watch out. Know your 9 times table facts, then division is quick.
Method. Use the 11 times table. Count up in 11s until you reach 66.
- Turn the division into a missing multiplication. 66 ÷ 11 asks: what do we multiply 11 by to get 66?66 ÷ 11 = ? means ? × 11 = 66
- Count up in 11s until you reach 66. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66
- Count how many numbers you said. The number of jumps is the answer.I said 6 numbers, so 6 × 11 = 66
- Write the answer. 66 ÷ 11 = 6
Check. Multiply back: 6 × 11 = 66. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 84.
- Turn the division into a missing multiplication. 84 ÷ 12 asks: what do we multiply 12 by to get 84?84 ÷ 12 = ? means ? × 12 = 84
- Count up in 12s until you reach 84. Each number you say is one more group of 12.12, 24, 36, 48, 60, 72, 84
- Count how many numbers you said. The number of jumps is the answer.I said 7 numbers, so 7 × 12 = 84
- Write the answer. 84 ÷ 12 = 7
Check. Multiply back: 7 × 12 = 84. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 11 times table. Count up in 11s until you reach 121.
- Turn the division into a missing multiplication. 121 ÷ 11 asks: what do we multiply 11 by to get 121?121 ÷ 11 = ? means ? × 11 = 121
- Count up in 11s until you reach 121. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121
- Count how many numbers you said. The number of jumps is the answer.I said 11 numbers, so 11 × 11 = 121
- Write the answer. 121 ÷ 11 = 11
Check. Multiply back: 11 × 11 = 121. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 144.
- Turn the division into a missing multiplication. 144 ÷ 12 asks: what do we multiply 12 by to get 144?144 ÷ 12 = ? means ? × 12 = 144
- Count up in 12s until you reach 144. Each number you say is one more group of 12.12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 12 = 144
- Write the answer. 144 ÷ 12 = 12
Check. Multiply back: 12 × 12 = 144. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 11 times table. Count up in 11s until you reach 99.
- Turn the division into a missing multiplication. 99 ÷ 11 asks: what do we multiply 11 by to get 99?99 ÷ 11 = ? means ? × 11 = 99
- Count up in 11s until you reach 99. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66, 77, 88, 99
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 11 = 99
- Write the answer. 99 ÷ 11 = 9
Check. Multiply back: 9 × 11 = 99. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 60.
- Turn the division into a missing multiplication. 60 ÷ 12 asks: what do we multiply 12 by to get 60?60 ÷ 12 = ? means ? × 12 = 60
- Count up in 12s until you reach 60. Each number you say is one more group of 12.12, 24, 36, 48, 60
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 12 = 60
- Write the answer. 60 ÷ 12 = 5
Check. Multiply back: 5 × 12 = 60. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 11 times table. Count up in 11s until you reach 132.
- Turn the division into a missing multiplication. 132 ÷ 11 asks: what do we multiply 11 by to get 132?132 ÷ 11 = ? means ? × 11 = 132
- Count up in 11s until you reach 132. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132
- Count how many numbers you said. The number of jumps is the answer.I said 12 numbers, so 12 × 11 = 132
- Write the answer. 132 ÷ 11 = 12
Check. Multiply back: 12 × 11 = 132. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 108.
- Turn the division into a missing multiplication. 108 ÷ 12 asks: what do we multiply 12 by to get 108?108 ÷ 12 = ? means ? × 12 = 108
- Count up in 12s until you reach 108. Each number you say is one more group of 12.12, 24, 36, 48, 60, 72, 84, 96, 108
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 12 = 108
- Write the answer. 108 ÷ 12 = 9
Check. Multiply back: 9 × 12 = 108. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 9 times table. Count up in 9s until you reach 45.
- Turn the division into a missing multiplication. 45 ÷ 9 asks: what do we multiply 9 by to get 45?45 ÷ 9 = ? means ? × 9 = 45
- Count up in 9s until you reach 45. Each number you say is one more group of 9.9, 18, 27, 36, 45
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 9 = 45
- Write the answer. 45 ÷ 9 = 5
Check. Multiply back: 5 × 9 = 45. ✓
Watch out. Know your 9 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 72.
- Turn the division into a missing multiplication. 72 ÷ 12 asks: what do we multiply 12 by to get 72?72 ÷ 12 = ? means ? × 12 = 72
- Count up in 12s until you reach 72. Each number you say is one more group of 12.12, 24, 36, 48, 60, 72
- Count how many numbers you said. The number of jumps is the answer.I said 6 numbers, so 6 × 12 = 72
- Write the answer. 72 ÷ 12 = 6
Check. Multiply back: 6 × 12 = 72. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 7 times table. Count up in 7s until you reach 35.
- Turn the division into a missing multiplication. 35 ÷ 7 asks: what do we multiply 7 by to get 35?35 ÷ 7 = ? means ? × 7 = 35
- Count up in 7s until you reach 35. Each number you say is one more group of 7.7, 14, 21, 28, 35
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 7 = 35
- Write the answer. 35 ÷ 7 = 5
Check. Multiply back: 5 × 7 = 35. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. Dividing by 8 is halving three times.
- Turn the division into a missing multiplication. 88 ÷ 8 asks: what do we multiply 8 by to get 88?88 ÷ 8 = ? means ? × 8 = 88
- Halve the number. 8 = 2 × 2 × 2, so we halve three times.half of 80 = 40, half of 8 = 4, so 40 + 4 = 44
- Halve again. half of 40 = 20, half of 4 = 2, so 20 + 2 = 22
- Halve a third time. half of 20 = 10, half of 2 = 1, so 10 + 1 = 11
- Write the answer. 88 ÷ 8 = 11
Check. Multiply back: 11 × 8 = 88. ✓
Watch out. Count your halves. Three halves divide by 8.
Method. Use the 6 times table. Count up in 6s until you reach 66.
- Turn the division into a missing multiplication. 66 ÷ 6 asks: what do we multiply 6 by to get 66?66 ÷ 6 = ? means ? × 6 = 66
- Count up in 6s until you reach 66. Each number you say is one more group of 6.6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66
- Count how many numbers you said. The number of jumps is the answer.I said 11 numbers, so 11 × 6 = 66
- Write the answer. 66 ÷ 6 = 11
Check. Multiply back: 11 × 6 = 66. ✓
Watch out. Know your 6 times table facts, then division is quick.
Method. Dividing by 4 is halving twice.
- Turn the division into a missing multiplication. 48 ÷ 4 asks: what do we multiply 4 by to get 48?48 ÷ 4 = ? means ? × 4 = 48
- Halve the number. 4 = 2 × 2, so we halve and then halve again.half of 40 = 20, half of 8 = 4, so 20 + 4 = 24
- Halve again. half of 20 = 10, half of 4 = 2, so 10 + 2 = 12
- Write the answer. 48 ÷ 4 = 12
Check. Multiply back: 12 × 4 = 48. ✓
Watch out. You must halve twice. Halving once gives the answer to a division by 2.
Method. Use the 11 times table. Count up in 11s until you reach 55.
- Turn the division into a missing multiplication. 55 ÷ 11 asks: what do we multiply 11 by to get 55?55 ÷ 11 = ? means ? × 11 = 55
- Count up in 11s until you reach 55. Each number you say is one more group of 11.11, 22, 33, 44, 55
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 11 = 55
- Write the answer. 55 ÷ 11 = 5
Check. Multiply back: 5 × 11 = 55. ✓
Watch out. Know your 11 times table facts, then division is quick.
Method. Use the 12 times table. Count up in 12s until you reach 36.
- Turn the division into a missing multiplication. 36 ÷ 12 asks: what do we multiply 12 by to get 36?36 ÷ 12 = ? means ? × 12 = 36
- Count up in 12s until you reach 36. Each number you say is one more group of 12.12, 24, 36
- Count how many numbers you said. The number of jumps is the answer.I said 3 numbers, so 3 × 12 = 36
- Write the answer. 36 ÷ 12 = 3
Check. Multiply back: 3 × 12 = 36. ✓
Watch out. Know your 12 times table facts, then division is quick.
Method. Use the 7 times table. Count up in 7s until you reach 49.
- Turn the division into a missing multiplication. 49 ÷ 7 asks: what do we multiply 7 by to get 49?49 ÷ 7 = ? means ? × 7 = 49
- Count up in 7s until you reach 49. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49
- Count how many numbers you said. The number of jumps is the answer.I said 7 numbers, so 7 × 7 = 49
- Write the answer. 49 ÷ 7 = 7
Check. Multiply back: 7 × 7 = 49. ✓
Watch out. Know your 7 times table facts, then division is quick.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 80 ÷ 10 asks: what do we multiply 10 by to get 80?80 ÷ 10 = ? means ? × 10 = 80
- Move the digits one place to the right. Tens become ones.80 → 8
- Write the answer. 80 ÷ 10 = 8
Check. Multiply back: 8 × 10 = 80. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Method. Use the 9 times table. Count up in 9s until you reach 63.
- Turn the division into a missing multiplication. 63 ÷ 9 asks: what do we multiply 9 by to get 63?63 ÷ 9 = ? means ? × 9 = 63
- Count up in 9s until you reach 63. Each number you say is one more group of 9.9, 18, 27, 36, 45, 54, 63
- Count how many numbers you said. The number of jumps is the answer.I said 7 numbers, so 7 × 9 = 63
- Write the answer. 63 ÷ 9 = 7
Check. Multiply back: 7 × 9 = 63. ✓
Watch out. Know your 9 times table facts, then division is quick.
Method. To divide by 5, double the number first and then divide by 10.
- Turn the division into a missing multiplication. 30 ÷ 5 asks: what do we multiply 5 by to get 30?30 ÷ 5 = ? means ? × 5 = 30
- Double the number. Doubling then dividing by 10 is the same as dividing by 5.double 30 = 60
- Divide by 10. Move the digits one place to the right.60 ÷ 10 = 6
- Write the answer. 30 ÷ 5 = 6
Check. Multiply back: 6 × 5 = 30. ✓
Watch out. Remember to do both steps: double, then divide by 10.
Method. Dividing by 1 does not change the number. Sharing between 1 person leaves everything with that person.
- Say what the division means. 12 ÷ 1 means: share 12 into 1 equal group.1 group gets all 12
- Think of a small example. Imagine sharing sweets with just one person.6 sweets shared with 1 person: they get all 6, so 6 ÷ 1 = 6
- Write the answer. One group means no sharing happens.12 ÷ 1 = 12
Check. Multiply back: 12 × 1 = 12. ✓
Watch out. Dividing by 1 does not give 1. It gives the same number.
Method. Any number divided by itself is 1. There is exactly one group of that size.
- Say what the division means. 7 ÷ 7 asks: how many groups of 7 fit into 7?one group of 7 fits
- Think of a small example. Imagine putting sweets into bags that each hold the whole amount.6 sweets in bags of 6: you fill 1 bag, so 6 ÷ 6 = 1
- Write the answer. 7 ÷ 7 = 1
Check. Multiply back: 1 × 7 = 7. ✓
Watch out. The answer is 1, not 7 and not 0.
Method. Zero shared between any number of groups is 0. There is nothing to share.
- Say what the division means. 0 ÷ 9 means: share 0 things between 9 groups.nothing to share
- Think of a small example. Imagine sharing an empty bag of sweets between 3 children.0 sweets shared between 3 children: each gets 0, so 0 ÷ 3 = 0
- Write the answer. Every group gets nothing.0 ÷ 9 = 0
Check. Multiply back: 0 × 9 = 0. ✓
Watch out. 0 ÷ 5 is 0. But you can never divide by 0: 5 ÷ 0 has no answer.
Method. Dividing by 1 does not change the number. Sharing between 1 person leaves everything with that person.
- Say what the division means. 100 ÷ 1 means: share 100 into 1 equal group.1 group gets all 100
- Think of a small example. Imagine sharing sweets with just one person.6 sweets shared with 1 person: they get all 6, so 6 ÷ 1 = 6
- Write the answer. One group means no sharing happens.100 ÷ 1 = 100
Check. Multiply back: 100 × 1 = 100. ✓
Watch out. Dividing by 1 does not give 1. It gives the same number.
Method. Any number divided by itself is 1. There is exactly one group of that size.
- Say what the division means. 12 ÷ 12 asks: how many groups of 12 fit into 12?one group of 12 fits
- Think of a small example. Imagine putting sweets into bags that each hold the whole amount.6 sweets in bags of 6: you fill 1 bag, so 6 ÷ 6 = 1
- Write the answer. 12 ÷ 12 = 1
Check. Multiply back: 1 × 12 = 12. ✓
Watch out. The answer is 1, not 12 and not 0.
Method. Dividing by 1 does not change the number. Sharing between 1 person leaves everything with that person.
- Say what the division means. 8 ÷ 1 means: share 8 into 1 equal group.1 group gets all 8
- Think of a small example. Imagine sharing sweets with just one person.6 sweets shared with 1 person: they get all 6, so 6 ÷ 1 = 6
- Write the answer. One group means no sharing happens.8 ÷ 1 = 8
Check. Multiply back: 8 × 1 = 8. ✓
Watch out. Dividing by 1 does not give 1. It gives the same number.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Two multiplication facts and two division facts use the same three numbers.
- Put the numbers in a fact triangle. The product goes at the top and the two factors at the bottom.
- Write the two multiplication facts. Multiply the bottom numbers in either order.3 × 8 = 24
8 × 3 = 24 - Write the two division facts. Start at the top and divide by one factor to get the other.24 ÷ 3 = 8
24 ÷ 8 = 3
Check. Check one fact: 3 × 8 = 24, so 24 ÷ 8 = 3. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Two multiplication facts and two division facts use the same three numbers.
- Put the numbers in a fact triangle. The product goes at the top and the two factors at the bottom.
- Write the two multiplication facts. Multiply the bottom numbers in either order.6 × 9 = 54
9 × 6 = 54 - Write the two division facts. Start at the top and divide by one factor to get the other.54 ÷ 6 = 9
54 ÷ 9 = 6
Check. Check one fact: 6 × 9 = 54, so 54 ÷ 9 = 6. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Both factors are 7, so there are only two facts.
- Put the numbers in a fact triangle. The product goes at the top and the factors at the bottom.
- Write the multiplication fact. Multiply the two numbers at the bottom to get the top.7 × 7 = 49
- Write the division fact. Start at the top and divide by the factor.49 ÷ 7 = 7
Check. Check one fact: 7 × 7 = 49, so 49 ÷ 7 = 7. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Two multiplication facts and two division facts use the same three numbers.
- Put the numbers in a fact triangle. The product goes at the top and the two factors at the bottom.
- Write the two multiplication facts. Multiply the bottom numbers in either order.12 × 5 = 60
5 × 12 = 60 - Write the two division facts. Start at the top and divide by one factor to get the other.60 ÷ 12 = 5
60 ÷ 5 = 12
Check. Check one fact: 12 × 5 = 60, so 60 ÷ 5 = 12. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 9 is multiplied by to make 63.9 × ? = 63
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 63 by 9.63 ÷ 9 = 7
- Write the missing number. 9 × 7 = 63
Check. Put it back: 9 × 7 = 63. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 8, makes 56.? × 8 = 56
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 56 by 8.56 ÷ 8 = 7
- Write the missing number. 7 × 8 = 56
Check. Put it back: 7 × 8 = 56. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 6 is multiplied by to make 72.6 × ? = 72
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 72 by 6.72 ÷ 6 = 12
- Write the missing number. 6 × 12 = 72
Check. Put it back: 6 × 12 = 72. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 7 gives 6.? ÷ 7 = 6
- Use the inverse (opposite) operation. The opposite of dividing by 7 is multiplying by 7.6 × 7 = 42
- Write the missing number. 42 ÷ 7 = 6
Check. Put it back: 42 ÷ 7 = 6. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 72 divided by the missing number makes 9.72 ÷ ? = 9
- Turn it into a multiplication. 9 lots of the missing number make 72.9 × ? = 72, so ? = 72 ÷ 9
- Work out the division. Count up in 9s, or use the 9 times table.72 ÷ 9 = 8
- Write the missing number. 72 ÷ 8 = 9
Check. Put it back: 72 ÷ 8 = 9. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 6 is multiplied by to make 54.6 × ? = 54
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 54 by 6.54 ÷ 6 = 9
- Write the missing number. 6 × 9 = 54
Check. Put it back: 6 × 9 = 54. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 12 gives 5.? ÷ 12 = 5
- Use the inverse (opposite) operation. The opposite of dividing by 12 is multiplying by 12.5 × 12 = 60
- Write the missing number. 60 ÷ 12 = 5
Check. Put it back: 60 ÷ 12 = 5. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 63 divided by the missing number makes 7.63 ÷ ? = 7
- Turn it into a multiplication. 7 lots of the missing number make 63.7 × ? = 63, so ? = 63 ÷ 7
- Work out the division. Count up in 7s, or use the 7 times table.63 ÷ 7 = 9
- Write the missing number. 63 ÷ 9 = 7
Check. Put it back: 63 ÷ 9 = 7. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 8 is multiplied by to make 96.96 = 8 × ?
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 96 by 8.96 ÷ 8 = 12
- Write the missing number. 8 × 12 = 96
Check. Put it back: 8 × 12 = 96. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 4 gives 11.? ÷ 4 = 11
- Use the inverse (opposite) operation. The opposite of dividing by 4 is multiplying by 4.11 × 4 = 44
- Write the missing number. 44 ÷ 4 = 11
Check. Put it back: 44 ÷ 4 = 11. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 110 divided by the missing number makes 10.110 ÷ ? = 10
- Turn it into a multiplication. 10 lots of the missing number make 110.10 × ? = 110, so ? = 110 ÷ 10
- Work out the division. Count up in 10s, or use the 10 times table.110 ÷ 10 = 11
- Write the missing number. 110 ÷ 11 = 10
Check. Put it back: 110 ÷ 11 = 10. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Check a division by multiplying. Multiply the answer by the number you divided by. You should get back to the number you started with.
- Write the division and the answer. We want to check if the answer is right.63 ÷ 7 = 8
- Multiply the answer by the number you divided by. Multiplication is the opposite of division. It should take us back to the start.8 × 7 = 56
- Compare with the number you started with. We started with 63.56 is not the same as 63
The correct answer: 9 × 7 = 63, so 63 ÷ 7 = 9 - Write the answer. Wrong. The answer is 9.
Check. 9 × 7 = 63. ✓
Watch out. If the multiplication does not take you back to the start, the division is wrong.
Method. Check a division by multiplying. Multiply the answer by the number you divided by. You should get back to the number you started with.
- Write the division and the answer. We want to check if the answer is right.56 ÷ 8 = 6
- Multiply the answer by the number you divided by. Multiplication is the opposite of division. It should take us back to the start.6 × 8 = 48
- Compare with the number you started with. We started with 56.48 is not the same as 56
The correct answer: 7 × 8 = 56, so 56 ÷ 8 = 7 - Write the answer. Wrong. The answer is 7.
Check. 7 × 8 = 56. ✓
Watch out. If the multiplication does not take you back to the start, the division is wrong.
Method. Check a division by multiplying. Multiply the answer by the number you divided by. You should get back to the number you started with.
- Write the division and the answer. We want to check if the answer is right.72 ÷ 9 = 8
- Multiply the answer by the number you divided by. Multiplication is the opposite of division. It should take us back to the start.8 × 9 = 72
- Compare with the number you started with. We started with 72.72 is the same as 72
- Write the answer. Correct
Check. 8 × 9 = 72. ✓
Watch out. If the multiplication does not take you back to the start, the division is wrong.
Method. Check a division by multiplying. Multiply the answer by the number you divided by. You should get back to the number you started with.
- Write the division and the answer. We want to check if the answer is right.45 ÷ 5 = 8
- Multiply the answer by the number you divided by. Multiplication is the opposite of division. It should take us back to the start.8 × 5 = 40
- Compare with the number you started with. We started with 45.40 is not the same as 45
The correct answer: 9 × 5 = 45, so 45 ÷ 5 = 9 - Write the answer. Wrong. The answer is 9.
Check. 9 × 5 = 45. ✓
Watch out. If the multiplication does not take you back to the start, the division is wrong.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 48. It is split into 6 equal parts. We want the size of one part.
- Choose the operation. Sharing equally means dividing.48 ÷ 6
- Use the times tables. Think: what do we multiply 6 by to get 48?8 × 6 = 48, so 48 ÷ 6 = 8
- Write the answer. Include the unit.8 stickers
Check. Multiply back: 8 × 6 = 48. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 84. Each bar is 12. We want to know how many bars.
- Choose the operation. We want to know how many groups of 12 fit into 84. That is a division.84 ÷ 12
- Use the times tables. Think: what do we multiply 12 by to get 84?7 × 12 = 84, so 84 ÷ 12 = 7
- Write the answer. Include the unit.7 boxes
Check. Multiply back: 7 × 12 = 84. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is £72. It is split into 9 equal parts. We want the size of one part.
- Choose the operation. Sharing equally means dividing.£72 ÷ 9
- Use the times tables. Think: what do we multiply 9 by to get 72?8 × 9 = 72, so 72 ÷ 9 = 8
- Write the answer. Include the unit.£8
Check. Multiply back: 8 × 9 = 72. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. Check Tom’s answer by multiplying it by 4. Then find the right answer.
- Check Tom’s answer. Multiply his answer by the number we divided by.8 × 4 = 32
- Compare. We should get back to 36, but we got 32.32 is not 36, so Tom is wrong.
- Find the correct answer. What do we multiply 4 by to get 36? Count in 4s: 4, 8, 12, 16, 20, 24, 28, 32, 36.9 × 4 = 36
- Write the answer. 36 ÷ 4 = 9
Check. Halve twice: 36 ÷ 2 = 18, 18 ÷ 2 = 9. ✓
Watch out. 4 × 8 = 32 is a true fact, but it is not the one we need. We need the fact that makes 36.
Method. Try some numbers. Look for one answer that is even and one answer that is odd.
- Try a number that gives an even answer. Halve it.8 ÷ 2 = 4, and 4 is even.
- Try a number that gives an odd answer. Halve it.6 ÷ 2 = 3, and 3 is odd.
- Decide. We found one of each.Sometimes
Check. 12 ÷ 2 = 6 (even), 14 ÷ 2 = 7 (odd). ✓
Watch out. To show “sometimes”, you need an example where it is true and an example where it is false.
A 56 ÷ 7
B 64 ÷ 9
C 72 ÷ 9
D 96 ÷ 12
E 80 ÷ 8
Method. Work out each division using the times tables, then pick the ones that make 8.
- Work out each division. Think “what times the number we divide by gives the number?”A: 56 ÷ 7 = 8
B: 64 ÷ 9: 9 × 7 = 63 and 9 × 8 = 72, so 64 is not in the 9 times table
C: 72 ÷ 9 = 8
D: 96 ÷ 12 = 8
E: 80 ÷ 8 = 10 - Pick the answers that are 8. A is 8, C is 8, D is 8. B has no whole-number answer, and E is 10.A, C and D
Check. Multiply back: 8 × 7 = 56, 8 × 9 = 72, 8 × 12 = 96. ✓
Watch out. Check B carefully. 64 is not in the 9 times table, so it does not divide by 9 exactly.
Method. List the pairs of numbers that multiply to make 36. Then add each pair and look for the one that makes 13.
- List the pairs that multiply to make 36. Use the times tables. Start with 1 × 36.1 × 36 = 36
2 × 18 = 36
3 × 12 = 36
4 × 9 = 36
6 × 6 = 36 - Add each pair. We want the pair whose sum is 13.1 × 36 = 36 1 + 36 = 37
2 × 18 = 36 2 + 18 = 20
3 × 12 = 36 3 + 12 = 15
4 × 9 = 36 4 + 9 = 13 13!
6 × 6 = 36 6 + 6 = 12 - Write the answer. 4 and 9
Check. 4 × 9 = 36 and 4 + 9 = 13. ✓
Watch out. Check both facts, the multiplication and the addition.
Factor pairs and multiplying three numbers
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
A factor of a number is a whole number that divides into it exactly, with nothing left over. A factor pair is two numbers that multiply to make the number. The factor pairs of 12 are 1 × 12, 2 × 6 and 3 × 4. Each pair makes a different array of 12 squares.
How to find all the factor pairs. Start at 1 and test each number in turn using the times tables: does it fit into the number exactly? Write down every pair you find. You can stop when the numbers meet in the middle, because after that you would only find the same pairs the other way round. Then write the factors in order. Every number has the pair 1 and itself.
Square numbers have a pair with the same number twice, like 6 × 6 = 36. The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18 and 36. Notice that 6 is only written once.
Factors and multiples. Factors are smaller than (or equal to) the number. Multiples are bigger than (or equal to) the number. The factors of 12 are 1, 2, 3, 4, 6, 12. The multiples of 12 are 12, 24, 36, 48...
Multiplying three numbers. Suppose a baker has 2 trays. Each tray has 3 rows of 4 buns. The number of buns is 2 × 3 × 4. You can multiply in any order and the answer is the same: (2 × 3) × 4 = 6 × 4 = 24, or 2 × (3 × 4) = 2 × 12 = 24. So look for a pair that is easy to multiply first. A great pair to look for is one that makes 10: 2 × 5. For 2 × 5 × 7, do 2 × 5 = 10, then 10 × 7 = 70.
Key words. A factor divides into a number exactly. A factor pair is two factors that multiply to make the number. A multiple is in the times table of a number.
Key ideas
- A factor pair is two numbers that multiply to make the number: 3 × 4 = 12.
- Test 1, 2, 3, ... in order. Stop when the numbers meet in the middle.
- Every number has 1 and itself as a factor pair.
- You can multiply three numbers in any order. Look for a pair that makes 10.
- Factors are small and multiples are big: factors of 12: 1, 2, 3, 4, 6, 12. Multiples of 12: 12, 24, 36...
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 12. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 12 = 12 (a pair: 1 and 12)
2 × 6 = 12 (a pair: 2 and 6)
3 × 4 = 12 (a pair: 3 and 4) - Stop when the numbers meet. After 3, the next factors would just be pairs we have already found the other way round.We can stop at 3.
- Write the factor pairs. 1 × 12 = 12
2 × 6 = 12
3 × 4 = 12 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 3, 4, 6, 12
Check. There are 6 factors: 1, 2, 3, 4, 6, 12. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 24. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 24 = 24 (a pair: 1 and 24)
2 × 12 = 24 (a pair: 2 and 12)
3 × 8 = 24 (a pair: 3 and 8)
4 × 6 = 24 (a pair: 4 and 6) - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 24 = 24
2 × 12 = 24
3 × 8 = 24
4 × 6 = 24 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 3, 4, 6, 8, 12, 24
Check. There are 8 factors: 1, 2, 3, 4, 6, 8, 12, 24. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 36. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 36 = 36 (a pair: 1 and 36)
2 × 18 = 36 (a pair: 2 and 18)
3 × 12 = 36 (a pair: 3 and 12)
4 × 9 = 36 (a pair: 4 and 9)
5 × 7 = 35 and 5 × 8 = 40: 36 is in between, so 5 is not a factor
6 × 6 = 36 (6 is paired with itself) - Stop when the numbers meet. After 6, the next factors would just be pairs we have already found the other way round.We can stop at 6.
- Write the factor pairs. 1 × 36 = 36
2 × 18 = 36
3 × 12 = 36
4 × 9 = 36
6 × 6 = 36 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 3, 4, 6, 9, 12, 18, 36
Check. There are 9 factors: 1, 2, 3, 4, 6, 9, 12, 18, 36. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 30. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 30 = 30 (a pair: 1 and 30)
2 × 15 = 30 (a pair: 2 and 15)
3 × 10 = 30 (a pair: 3 and 10)
4 × 7 = 28 and 4 × 8 = 32: 30 is in between, so 4 is not a factor
5 × 6 = 30 (a pair: 5 and 6) - Stop when the numbers meet. After 5, the next factors would just be pairs we have already found the other way round.We can stop at 5.
- Write the factor pairs. 1 × 30 = 30
2 × 15 = 30
3 × 10 = 30
5 × 6 = 30 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 3, 5, 6, 10, 15, 30
Check. There are 8 factors: 1, 2, 3, 5, 6, 10, 15, 30. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Method. Check if 42 is in the 7 times table. If it is, 7 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 7 is a factor of 42 only if 42 is in the 7 times table.Is 42 in the 7 times table?
- Count up in 7s. Find the multiples of 7 close to 42.7 × 6 = 42
- Answer. Yes. 7 × 6 = 42, so 7 is a factor of 42.
Check. 42 ÷ 7 = 6 exactly, with nothing left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 42 is in the 5 times table. If it is, 5 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 5 is a factor of 42 only if 42 is in the 5 times table.Is 42 in the 5 times table?
- Count up in 5s. Find the multiples of 5 on each side of 42.5 × 8 = 40
5 × 9 = 45 - Answer. 42 is between those two multiples, so it is not in the 5 times table.No. 5 is not a factor of 42.
Check. 42 ÷ 5 = 8 remainder 2. There is something left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 3 is a times table fact.2 × 3 = 6
- Multiply the answer by the last number, 4. 6 × 4 is a times table fact.6 + 6 = 12
double 10 = 20, double 2 = 4, so 20 + 4 = 24
6 × 4 = 24 - Write the answer. 2 × 3 × 4 = 24
Check. Try a different order: 3 × 4 = 12, then 12 × 2 = 24. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 5 = 10, and multiplying by 10 is easy.2 × 5 = 10
- Multiply the answer by the last number, 7. 10 × 7 is a times table fact.7 tens
7 → 70
10 × 7 = 70 - Write the answer. 2 × 5 × 7 = 70
Check. Try a different order: 5 × 7 = 35, then 35 × 2 = 70. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 4 × 5 = 20, a multiple of 10, which is easy to multiply.4 × 5 = 20
- Multiply the answer by the last number, 3. 20 is 2 tens. Work out 2 × 3, then say that many tens.2 × 3 = 6, so 2 tens × 3 = 6 tens
6 tens = 60 - Write the answer. 4 × 3 × 5 = 60
Check. Try a different order: 5 × 3 = 15, then 15 × 4 = 60. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Watch out
Do not forget 1 and the number itself! They are always a factor pair. Also, a factor pair must multiply to make the number exactly: 3 × 5 = 15, but 3 and 5 are not a factor pair of 16. When you multiply three numbers, only multiply two at a time. Do the first pair, then multiply the answer by the third number.Exercise 3F Factor pairs and multiplying three numbers
Non-calculatorKey words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 8. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 8 = 8 (a pair: 1 and 8)
2 × 4 = 8 (a pair: 2 and 4) - Stop when the numbers meet. After 2, the next factors would just be pairs we have already found the other way round.We can stop at 2.
- Write the factor pairs. 1 × 8 = 8
2 × 4 = 8 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 4, 8
Check. There are 4 factors: 1, 2, 4, 8. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 15. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 15 = 15 (a pair: 1 and 15)
2 × 7 = 14 and 2 × 8 = 16: 15 is in between, so 2 is not a factor
3 × 5 = 15 (a pair: 3 and 5) - Stop when the numbers meet. After 3, the next factors would just be pairs we have already found the other way round.We can stop at 3.
- Write the factor pairs. 1 × 15 = 15
3 × 5 = 15 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 3, 5, 15
Check. There are 4 factors: 1, 3, 5, 15. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 20. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 20 = 20 (a pair: 1 and 20)
2 × 10 = 20 (a pair: 2 and 10)
3 × 6 = 18 and 3 × 7 = 21: 20 is in between, so 3 is not a factor
4 × 5 = 20 (a pair: 4 and 5) - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 20 = 20
2 × 10 = 20
4 × 5 = 20 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 4, 5, 10, 20
Check. There are 6 factors: 1, 2, 4, 5, 10, 20. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 28. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 28 = 28 (a pair: 1 and 28)
2 × 14 = 28 (a pair: 2 and 14)
3 × 9 = 27 and 3 × 10 = 30: 28 is in between, so 3 is not a factor
4 × 7 = 28 (a pair: 4 and 7)
5 × 5 = 25 and 5 × 6 = 30: 28 is in between, so 5 is not a factor - Stop when the numbers meet. After 5, the next factors would just be pairs we have already found the other way round.We can stop at 5.
- Write the factor pairs. 1 × 28 = 28
2 × 14 = 28
4 × 7 = 28 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 4, 7, 14, 28
Check. There are 6 factors: 1, 2, 4, 7, 14, 28. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 10. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 10 = 10 (a pair: 1 and 10)
2 × 5 = 10 (a pair: 2 and 5)
3 × 3 = 9 and 3 × 4 = 12: 10 is in between, so 3 is not a factor - Stop when the numbers meet. After 3, the next factors would just be pairs we have already found the other way round.We can stop at 3.
- Write the factor pairs. 1 × 10 = 10
2 × 5 = 10 - List all the factors in order. Each number in a pair is a factor.1, 2, 5, 10
Check. There are 4 factors: 1, 2, 5, 10. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 16. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 16 = 16 (a pair: 1 and 16)
2 × 8 = 16 (a pair: 2 and 8)
3 × 5 = 15 and 3 × 6 = 18: 16 is in between, so 3 is not a factor
4 × 4 = 16 (4 is paired with itself) - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 16 = 16
2 × 8 = 16
4 × 4 = 16 - List all the factors in order. Each number in a pair is a factor.1, 2, 4, 8, 16
Check. There are 5 factors: 1, 2, 4, 8, 16. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 18. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 18 = 18 (a pair: 1 and 18)
2 × 9 = 18 (a pair: 2 and 9)
3 × 6 = 18 (a pair: 3 and 6)
4 × 4 = 16 and 4 × 5 = 20: 18 is in between, so 4 is not a factor - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 18 = 18
2 × 9 = 18
3 × 6 = 18 - List all the factors in order. Each number in a pair is a factor.1, 2, 3, 6, 9, 18
Check. There are 6 factors: 1, 2, 3, 6, 9, 18. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 21. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 21 = 21 (a pair: 1 and 21)
2 × 10 = 20 and 2 × 11 = 22: 21 is in between, so 2 is not a factor
3 × 7 = 21 (a pair: 3 and 7)
4 × 5 = 20 and 4 × 6 = 24: 21 is in between, so 4 is not a factor - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 21 = 21
3 × 7 = 21 - List all the factors in order. Each number in a pair is a factor.1, 3, 7, 21
Check. There are 4 factors: 1, 3, 7, 21. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Method. Check if 24 is in the 6 times table. If it is, 6 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 6 is a factor of 24 only if 24 is in the 6 times table.Is 24 in the 6 times table?
- Count up in 6s. Find the multiples of 6 close to 24.6 × 4 = 24
- Answer. Yes. 6 × 4 = 24, so 6 is a factor of 24.
Check. 24 ÷ 6 = 4 exactly, with nothing left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 36 is in the 5 times table. If it is, 5 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 5 is a factor of 36 only if 36 is in the 5 times table.Is 36 in the 5 times table?
- Count up in 5s. Find the multiples of 5 on each side of 36.5 × 7 = 35
5 × 8 = 40 - Answer. 36 is between those two multiples, so it is not in the 5 times table.No. 5 is not a factor of 36.
Check. 36 ÷ 5 = 7 remainder 1. There is something left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 56 is in the 8 times table. If it is, 8 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 8 is a factor of 56 only if 56 is in the 8 times table.Is 56 in the 8 times table?
- Count up in 8s. Find the multiples of 8 close to 56.8 × 7 = 56
- Answer. Yes. 8 × 7 = 56, so 8 is a factor of 56.
Check. 56 ÷ 8 = 7 exactly, with nothing left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 72 is in the 9 times table. If it is, 9 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 9 is a factor of 72 only if 72 is in the 9 times table.Is 72 in the 9 times table?
- Count up in 9s. Find the multiples of 9 close to 72.9 × 8 = 72
- Answer. Yes. 9 × 8 = 72, so 9 is a factor of 72.
Check. 72 ÷ 9 = 8 exactly, with nothing left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 50 is in the 7 times table. If it is, 7 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 7 is a factor of 50 only if 50 is in the 7 times table.Is 50 in the 7 times table?
- Count up in 7s. Find the multiples of 7 on each side of 50.7 × 7 = 49
7 × 8 = 56 - Answer. 50 is between those two multiples, so it is not in the 7 times table.No. 7 is not a factor of 50.
Check. 50 ÷ 7 = 7 remainder 1. There is something left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Method. Check if 96 is in the 12 times table. If it is, 12 is a factor.
- Say what we need to check. A factor divides into the number exactly, with nothing left over. So 12 is a factor of 96 only if 96 is in the 12 times table.Is 96 in the 12 times table?
- Count up in 12s. Find the multiples of 12 close to 96.12 × 8 = 96
- Answer. Yes. 12 × 8 = 96, so 12 is a factor of 96.
Check. 96 ÷ 12 = 8 exactly, with nothing left over. ✓
Watch out. A factor must divide in exactly, with nothing left over.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 36. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 36 = 36 (a pair: 1 and 36)
2 × 18 = 36 (a pair: 2 and 18)
3 × 12 = 36 (a pair: 3 and 12)
4 × 9 = 36 (a pair: 4 and 9)
5 × 7 = 35 and 5 × 8 = 40: 36 is in between, so 5 is not a factor
6 × 6 = 36 (6 is paired with itself) - Stop when the numbers meet. After 6, the next factors would just be pairs we have already found the other way round.We can stop at 6.
- Write the factor pairs. 1 × 36 = 36
2 × 18 = 36
3 × 12 = 36
4 × 9 = 36
6 × 6 = 36 - List all the factors in order. Each number in a pair is a factor.1, 2, 3, 4, 6, 9, 12, 18, 36
Check. There are 9 factors: 1, 2, 3, 4, 6, 9, 12, 18, 36. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 49. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 49 = 49 (a pair: 1 and 49)
2 × 24 = 48 and 2 × 25 = 50: 49 is in between, so 2 is not a factor
3 × 16 = 48 and 3 × 17 = 51: 49 is in between, so 3 is not a factor
4 × 12 = 48 and 4 × 13 = 52: 49 is in between, so 4 is not a factor
5 × 9 = 45 and 5 × 10 = 50: 49 is in between, so 5 is not a factor
6 × 8 = 48 and 6 × 9 = 54: 49 is in between, so 6 is not a factor
7 × 7 = 49 (7 is paired with itself) - Stop when the numbers meet. After 7, the next factors would just be pairs we have already found the other way round.We can stop at 7.
- Write the factor pairs. 1 × 49 = 49
7 × 7 = 49 - List all the factors in order. Each number in a pair is a factor.1, 7, 49
Check. There are 3 factors: 1, 7, 49. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 25. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 25 = 25 (a pair: 1 and 25)
2 × 12 = 24 and 2 × 13 = 26: 25 is in between, so 2 is not a factor
3 × 8 = 24 and 3 × 9 = 27: 25 is in between, so 3 is not a factor
4 × 6 = 24 and 4 × 7 = 28: 25 is in between, so 4 is not a factor
5 × 5 = 25 (5 is paired with itself) - Stop when the numbers meet. After 5, the next factors would just be pairs we have already found the other way round.We can stop at 5.
- Write the factor pairs. 1 × 25 = 25
5 × 5 = 25 - List all the factors in order. Each number in a pair is a factor.1, 5, 25
Check. There are 3 factors: 1, 5, 25. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 5 = 10, and multiplying by 10 is easy.2 × 5 = 10
- Multiply the answer by the last number, 7. 10 × 7 is a times table fact.7 tens
7 → 70
10 × 7 = 70 - Write the answer. 2 × 5 × 7 = 70
Check. Try a different order: 5 × 7 = 35, then 35 × 2 = 70. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 4 × 5 = 20, a multiple of 10, which is easy to multiply.4 × 5 = 20
- Multiply the answer by the last number, 3. 20 is 2 tens. Work out 2 × 3, then say that many tens.2 × 3 = 6, so 2 tens × 3 = 6 tens
6 tens = 60 - Write the answer. 4 × 3 × 5 = 60
Check. Try a different order: 5 × 3 = 15, then 15 × 4 = 60. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 3 is a times table fact.2 × 3 = 6
- Multiply the answer by the last number, 4. 6 × 4 is a times table fact.6 + 6 = 12
double 10 = 20, double 2 = 4, so 20 + 4 = 24
6 × 4 = 24 - Write the answer. 2 × 3 × 4 = 24
Check. Try a different order: 3 × 4 = 12, then 12 × 2 = 24. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 5 × 2 = 10, and multiplying by 10 is easy.5 × 2 = 10
- Multiply the answer by the last number, 9. 10 × 9 is a times table fact.9 tens
9 → 90
10 × 9 = 90 - Write the answer. 5 × 2 × 9 = 90
Check. Try a different order: 2 × 9 = 18, then 18 × 5 = 90. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 3 × 2 is a times table fact.3 × 2 = 6
- Multiply the answer by the last number, 6. 6 × 6 is a times table fact.5 × 6 = 30
30 + 6 = 36
6 × 6 = 36 - Write the answer. 6 × 3 × 2 = 36
Check. Try a different order: 2 × 6 = 12, then 12 × 3 = 36. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 5 = 10, and multiplying by 10 is easy.2 × 5 = 10
- Multiply the answer by the last number, 8. 10 × 8 is a times table fact.8 tens
8 → 80
10 × 8 = 80 - Write the answer. 2 × 5 × 8 = 80
Check. Try a different order: 5 × 8 = 40, then 40 × 2 = 80. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 3 × 3 is a times table fact.3 × 3 = 9
- Multiply the answer by the last number, 4. 9 × 4 is a times table fact.9 + 9 = 18
double 10 = 20, double 8 = 16, so 20 + 16 = 36
9 × 4 = 36 - Write the answer. 3 × 3 × 4 = 36
Check. Try a different order: 3 × 4 = 12, then 12 × 3 = 36. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 4 × 5 = 20, a multiple of 10, which is easy to multiply.4 × 5 = 20
- Multiply the answer by the last number, 5. 20 is 2 tens. Work out 2 × 5, then say that many tens.2 × 5 = 10, so 2 tens × 5 = 10 tens
10 tens = 100 - Write the answer. 4 × 5 × 5 = 100
Check. Try a different order: 5 × 5 = 25, then 25 × 4 = 100. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Method. The number of rows and the number in each row are a factor pair of 24. Find all the factor pairs.
- Find the factor pairs of 24. Test 1, 2, 3, ... with the times tables.1 × 24 = 24
2 × 12 = 24
3 × 8 = 24
4 × 6 = 24 - Check 5 and 6. 5 is not a factor (5 × 4 = 20, 5 × 5 = 25). 6 is paired with 4 already.No new pairs.
- Write the ways to arrange the chairs. Each pair can be used as rows × chairs in a row, or the other way round.
Check. There are 8 factors of 24 (1, 2, 3, 4, 6, 8, 12, 24), which make 4 pairs. ✓
Watch out. Rows of 1 (a long line of 24) and 24 rows of 1 count, but most people would not choose them!
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Write the calculation. 3 trays, each with 4 rows of 6 buns. Multiply the three numbers.3 × 4 × 6
- Choose two numbers to multiply first. 3 × 4 is a times table fact.3 × 4 = 12
- Multiply the answer by the last number, 6. 12 × 6 is a times table fact.10 × 6 = 60
6 + 6 = 12
60 + 12 = 72
12 × 6 = 72 - Write the answer. 3 × 4 × 6 = 72
Check. Try a different order: 4 × 6 = 24, then 24 × 3 = 72. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Write the calculation. 4 crates, each with 5 rows of 6 bottles. Multiply the three numbers.4 × 5 × 6
- Choose two numbers to multiply first. 4 × 5 = 20, a multiple of 10, which is easy to multiply.4 × 5 = 20
- Multiply the answer by the last number, 6. 20 is 2 tens. Work out 2 × 6, then say that many tens.2 × 6 = 12, so 2 tens × 6 = 12 tens
12 tens = 120 - Write the answer. 4 × 5 × 6 = 120
Check. Try a different order: 5 × 6 = 30, then 30 × 4 = 120. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Key words. A counter-example is one example that shows a rule is not always true.
Method. To show that a rule is wrong, find one example where it does not work. This is called a counter-example.
- Try a small number. 5 has only the factors 1 and 5, so the rule works for 5. But does it work for every number?5 × 1 = 5: factors 1 and 5
- Try a bigger number. Find all the factors of 12.1 × 12, 2 × 6, 3 × 4: the factors are 1, 2, 3, 4, 6, 12
- Answer Amira. 12 has more than two factors.No. 12 has 6 factors, not 2.
Check. Check one: 12 ÷ 4 = 3 exactly, so 4 is a factor. ✓
Watch out. Prime numbers (like 5, 7 and 13) do have exactly two factors. But most numbers have more.
Method. Test each number. A factor of 24 must be in a pair that multiplies to make 24.
- Write the factor pairs of 24. Use the times tables.1 × 24, 2 × 12, 3 × 8, 4 × 6
- Compare with the list. 1, 2, 3, 4, 6, 8 and 12 are all in the pairs.Only 9 is not in a pair.
- Check 9. 9 × 2 = 18 and 9 × 3 = 27. 24 is in between.9
Check. The factors of 24 are 1, 2, 3, 4, 6, 8, 12 and 24. ✓
Watch out. 9 is in the 3 times table, but being a multiple of 3 does not make it a factor of 24.
Method. Think about dividing by 1.
- Divide by 1. A number divided by 1 is the same number, with nothing left over.12 ÷ 1 = 12 7 ÷ 1 = 7
- Decide. It works for every number.Always
Check. n × 1 = n for any number. ✓
Watch out. This is why every factor list starts with 1.
Method. 24 is double 12, so look at what happens when you double.
- List the factors of 12. 1, 2, 3, 4, 6, 12
- Test them on 24. 24 = 2 × 12, so anything that divides 12 divides 24.24 ÷ 1, 24 ÷ 2, 24 ÷ 3, 24 ÷ 4, 24 ÷ 6, 24 ÷ 12 all work
- Decide. Always
Check. 24 ÷ 12 = 2 and 24 ÷ 6 = 4. ✓
Watch out. This only works because 24 is a multiple of 12.
Method. Think about the factor pair 1 and the number itself.
- Try an example where it works. 3 is a factor of 12 and 3 < 12
- Try an example where it does not work. Every number is a factor of itself.12 is a factor of 12 and 12 is not smaller than 12
- Decide. Sometimes
Check. 12 ÷ 12 = 1. ✓
Watch out. A number is its own biggest factor.
Method. List the factors of both numbers and count them.
- List the factors of 24. Find all the factor pairs.1, 2, 3, 4, 6, 8, 12, 24 (8 factors)
- List the factors of 30. Find all the factor pairs.1, 2, 3, 5, 6, 10, 15, 30 (8 factors)
- Compare. They both have 8.No. Zoe is not right. 24 and 30 both have 8 factors.
Check. Count pairs: 24 has 4 pairs, 30 has 4 pairs. ✓
Watch out. A bigger number does not always have more factors. For example 29 has only two.
Method. The hint says to try square numbers. A square number has a factor pair with the same number twice, so its factors are an odd count. Check each square up to 50.
- List the square numbers up to 50. 1, 4, 9, 16, 25, 36, 49
- Find the factors of each. Count them.1: 1 factor
4: 1, 2, 4 (3 factors)
9: 1, 3, 9 (3 factors)
16: 1, 2, 4, 8, 16 (5 factors)
25: 1, 5, 25 (3 factors)
36: 1, 2, 3, 4, 6, 9, 12, 18, 36 (9 factors)
49: 1, 7, 49 (3 factors) - Pick the ones with exactly three factors. 4, 9, 25 and 49
Check. Each of these is a number times itself where the number has only two factors: 2 × 2, 3 × 3, 5 × 5, 7 × 7. ✓
Watch out. Check that the numbers that are not square (like 6 or 10) have an even number of factors.
Method. There are only four ways to choose three numbers from four. Try each way.
- List all the ways. Leave out one number each time.2 × 3 × 4 = 24
2 × 3 × 5 = 30
2 × 4 × 5 = 40
3 × 4 × 5 = 60 - Find the one that makes 60. 3 × 4 × 5 = 12 × 5 = 60
Check. Leaving out 2 gives 3, 4, 5. ✓
Watch out. Check that you used three different numbers.
Using known facts, word problems and the times table check
Printable: Worksheet (PDF) · Answers (PDF) · Open this lesson on its own page
Use a fact you know to work out new facts. Suppose you know 6 × 7 = 42. Then 60 is 6 tens, so 60 × 7 is 6 tens × 7 = 42 tens = 420. In the same way, 6 × 70 = 420 (6 groups of 7 tens) and 600 × 7 = 4,200 (42 hundreds). The digits stay the same and the zeros move along. Division works the same way: 420 ÷ 7 = 60 and 4,200 ÷ 7 = 600.
You can also get a new fact from a nearby fact. Add or take away one group: 7 × 7 is 6 × 7 plus one more 7, which is 42 + 7 = 49. Double: 12 × 7 is double 6 × 7, so double 42 is 84. Halve: 3 × 7 is half of 6 × 7, so half of 42 is 21.
Word problems. Read the problem twice. Draw a bar model. If you know the size of each group and the number of groups, multiply to find the total. If you know the total and want to share it equally, or find how many groups, divide. Write the unit (like £, cm or “pens”) in your answer.
The times tables check. In Year 4 you take a short check on the computer. There are 25 questions like 7 × 8 = ?, and you get 6 seconds for each one. The best preparation is a little practice every day. Make sure you know the ten tricky facts where both numbers are from 6 to 9 (shaded below), and use the tricks in this chapter to build any fact in a flash. The practice sets in this section use the same style: 25 questions, 6 seconds each. Cover the answers and see how many you can do in time!
Key words. A known fact is a fact you can recall. A derived fact is a new fact that you work out from a known fact.
Key ideas
- Use a known fact and place value: 6 × 7 = 42, so 60 × 7 = 420, 6 × 70 = 420 and 600 × 7 = 4,200.
- Division too: 42 ÷ 7 = 6, so 420 ÷ 7 = 60.
- Nearby facts: add or take away one group. Double or halve the number of groups.
- Equal groups with a total to find: multiply. A total to share or split into groups: divide.
- Times tables check: 25 questions, 6 seconds each.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 6 × 7 = 42, and place value. 60 is 6 tens, so the answer is 42 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.6 × 7 = 42
- Say the bigger number in tens. 60 is 6 tens.60 = 6 tens
- Multiply, using the known fact. 6 tens × 7 = 42 tens, because 6 × 7 = 42.6 × 7 = 42, so 6 tens × 7 = 42 tens
- Change 42 tens back to a number. 1 ten is 10, so 42 tens is 42 × 10. 42 tens = 420
- Write the answer. 60 × 7 = 420
Check. Divide back: 420 ÷ 7 = 60. ✓
Watch out. The answer is 42 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 4 × 8 = 32, and place value. 80 is 8 tens, so the answer is 32 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.4 × 8 = 32
- Say the bigger number in tens. 80 is 8 tens.80 = 8 tens
- Multiply, using the known fact. 8 tens × 4 = 32 tens, because 8 × 4 = 32.8 × 4 = 32, so 8 tens × 4 = 32 tens
- Change 32 tens back to a number. 1 ten is 10, so 32 tens is 32 × 10. 32 tens = 320
- Write the answer. 4 × 80 = 320
Check. Divide back: 320 ÷ 80 = 4. ✓
Watch out. The answer is 32 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 9 × 5 = 45, and place value. 900 is 9 hundreds, so the answer is 45 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.9 × 5 = 45
- Say the bigger number in hundreds. 900 is 9 hundreds.900 = 9 hundreds
- Multiply, using the known fact. 9 hundreds × 5 = 45 hundreds, because 9 × 5 = 45.9 × 5 = 45, so 9 hundreds × 5 = 45 hundreds
- Change 45 hundreds back to a number. 1 hundred is 100, so 45 hundreds is 45 × 100. 45 hundreds = 4,500
- Write the answer. 900 × 5 = 4,500
Check. Divide back: 4,500 ÷ 5 = 900. ✓
Watch out. The answer is 45 hundreds, which has 2 zeros on the end. Count the zeros carefully.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 56 ÷ 8 = 7, and place value. 560 is 56 tens, so the answer is 7 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.56 ÷ 8 = 7
- Say the big number in tens. 560 is 56 tens.560 = 56 tens
- Divide, using the known fact. 56 tens ÷ 8 = 7 tens, because 56 ÷ 8 = 7.56 ÷ 8 = 7, so 56 tens ÷ 8 = 7 tens
- Change 7 tens back to a number. Put the zeros back.7 tens = 70
- Write the answer. 560 ÷ 8 = 70
Check. Multiply back: 70 × 8 = 560. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 36 ÷ 9 = 4, and place value. 3,600 is 36 hundreds, so the answer is 4 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.36 ÷ 9 = 4
- Say the big number in hundreds. 3,600 is 36 hundreds.3,600 = 36 hundreds
- Divide, using the known fact. 36 hundreds ÷ 9 = 4 hundreds, because 36 ÷ 9 = 4.36 ÷ 9 = 4, so 36 hundreds ÷ 9 = 4 hundreds
- Change 4 hundreds back to a number. Put the zeros back.4 hundreds = 400
- Write the answer. 3,600 ÷ 9 = 400
Check. Multiply back: 400 × 9 = 3,600. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 7 is one more than 6, so add one more group of 8 to the answer to 6 × 8.
- Write the fact you know. We start from the fact we know.6 × 8 = 48
- Compare 7 with 6. 7 is one more than 6, so we need one more group of 8.7 = 6 + 1
- Add one more group. One group is 8.48 + 8 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 8 = 7. ✓
Watch out. Add 8, the size of one group, not 7 or 1.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 12 is double 6, so double the answer to 6 × 7.
- Write the fact you know. We start from the fact we know.6 × 7 = 42
- Compare 12 with 6. 12 is double 6, so 12 groups of 7 are double 6 groups of 7.12 = 2 × 6
- Double the known answer. double 40 = 80, double 2 = 4, so 80 + 4 = 84
- Write the answer. 12 × 7 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Doubling the number of groups doubles the total. Do not double the other number as well.
Method. Two steps. First find how many pencils Leo buys by multiplying. Then take away the pencils he gives away.
- Draw a bar model for step 1. 6 equal packs of 12. We want the total.
- Step 1: multiply. Equal groups, so multiply.10 × 6 = 60
6 + 6 = 12
60 + 12 = 72
6 × 12 = 72 - Step 2: take away. Leo gives 15 pencils away. Take 10 first, then 5.72 − 10 = 62, then 62 − 5 = 57
- Write the answer. 57 pencils
Check. Add back: 57 + 15 = 72 and 72 ÷ 6 = 12. ✓
Watch out. The answer to step 1 (72) is not the final answer. Check what the question asks for.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 72. It is split into 8 equal parts. We want the size of one part.
- Choose the operation. Sharing equally means dividing.72 ÷ 8
- Use the times tables. Think: what do we multiply 8 by to get 72?9 × 8 = 72, so 72 ÷ 8 = 9
- Write the answer. Include the unit.9 apples
Check. Multiply back: 9 × 8 = 72. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Watch out
Keep the zeros! 60 × 7 is 420, not 42. Write the known fact first, then say how many tens or hundreds you have. In word problems, do not choose multiply or divide because of one word in the question. Draw a bar model and decide if you know the total or the size of each group.Exercise 3G Using known facts
Non-calculatorKey words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 6 × 4 = 24, and place value. 60 is 6 tens, so the answer is 24 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.6 × 4 = 24
- Say the bigger number in tens. 60 is 6 tens.60 = 6 tens
- Multiply, using the known fact. 6 tens × 4 = 24 tens, because 6 × 4 = 24.6 × 4 = 24, so 6 tens × 4 = 24 tens
- Change 24 tens back to a number. 1 ten is 10, so 24 tens is 24 × 10. 24 tens = 240
- Write the answer. 60 × 4 = 240
Check. Divide back: 240 ÷ 4 = 60. ✓
Watch out. The answer is 24 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 6 × 4 = 24, and place value. 40 is 4 tens, so the answer is 24 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.6 × 4 = 24
- Say the bigger number in tens. 40 is 4 tens.40 = 4 tens
- Multiply, using the known fact. 4 tens × 6 = 24 tens, because 4 × 6 = 24.4 × 6 = 24, so 4 tens × 6 = 24 tens
- Change 24 tens back to a number. 1 ten is 10, so 24 tens is 24 × 10. 24 tens = 240
- Write the answer. 6 × 40 = 240
Check. Divide back: 240 ÷ 40 = 6. ✓
Watch out. The answer is 24 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 6 × 4 = 24, and place value. 600 is 6 hundreds, so the answer is 24 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.6 × 4 = 24
- Say the bigger number in hundreds. 600 is 6 hundreds.600 = 6 hundreds
- Multiply, using the known fact. 6 hundreds × 4 = 24 hundreds, because 6 × 4 = 24.6 × 4 = 24, so 6 hundreds × 4 = 24 hundreds
- Change 24 hundreds back to a number. 1 hundred is 100, so 24 hundreds is 24 × 100. 24 hundreds = 2,400
- Write the answer. 600 × 4 = 2,400
Check. Divide back: 2,400 ÷ 4 = 600. ✓
Watch out. The answer is 24 hundreds, which has 2 zeros on the end. Count the zeros carefully.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 24 ÷ 4 = 6, and place value. 240 is 24 tens, so the answer is 6 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.24 ÷ 4 = 6
- Say the big number in tens. 240 is 24 tens.240 = 24 tens
- Divide, using the known fact. 24 tens ÷ 4 = 6 tens, because 24 ÷ 4 = 6.24 ÷ 4 = 6, so 24 tens ÷ 4 = 6 tens
- Change 6 tens back to a number. Put the zeros back.6 tens = 60
- Write the answer. 240 ÷ 4 = 60
Check. Multiply back: 60 × 4 = 240. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 24 ÷ 4 = 6, and place value. 2,400 is 24 hundreds, so the answer is 6 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.24 ÷ 4 = 6
- Say the big number in hundreds. 2,400 is 24 hundreds.2,400 = 24 hundreds
- Divide, using the known fact. 24 hundreds ÷ 4 = 6 hundreds, because 24 ÷ 4 = 6.24 ÷ 4 = 6, so 24 hundreds ÷ 4 = 6 hundreds
- Change 6 hundreds back to a number. Put the zeros back.6 hundreds = 600
- Write the answer. 2,400 ÷ 4 = 600
Check. Multiply back: 600 × 4 = 2,400. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 24 ÷ 6 = 4, and place value. 240 is 24 tens, so the answer is 4 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.24 ÷ 6 = 4
- Say the big number in tens. 240 is 24 tens.240 = 24 tens
- Divide, using the known fact. 24 tens ÷ 6 = 4 tens, because 24 ÷ 6 = 4.24 ÷ 6 = 4, so 24 tens ÷ 6 = 4 tens
- Change 4 tens back to a number. Put the zeros back.4 tens = 40
- Write the answer. 240 ÷ 6 = 40
Check. Multiply back: 40 × 6 = 240. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 8 × 7 = 56, and place value. 80 is 8 tens, so the answer is 56 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.8 × 7 = 56
- Say the bigger number in tens. 80 is 8 tens.80 = 8 tens
- Multiply, using the known fact. 8 tens × 7 = 56 tens, because 8 × 7 = 56.8 × 7 = 56, so 8 tens × 7 = 56 tens
- Change 56 tens back to a number. 1 ten is 10, so 56 tens is 56 × 10. 56 tens = 560
- Write the answer. 80 × 7 = 560
Check. Divide back: 560 ÷ 7 = 80. ✓
Watch out. The answer is 56 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 8 × 7 = 56, and place value. 70 is 7 tens, so the answer is 56 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.8 × 7 = 56
- Say the bigger number in tens. 70 is 7 tens.70 = 7 tens
- Multiply, using the known fact. 7 tens × 8 = 56 tens, because 7 × 8 = 56.7 × 8 = 56, so 7 tens × 8 = 56 tens
- Change 56 tens back to a number. 1 ten is 10, so 56 tens is 56 × 10. 56 tens = 560
- Write the answer. 8 × 70 = 560
Check. Divide back: 560 ÷ 70 = 8. ✓
Watch out. The answer is 56 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 8 × 7 = 56, and place value. 800 is 8 hundreds, so the answer is 56 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.8 × 7 = 56
- Say the bigger number in hundreds. 800 is 8 hundreds.800 = 8 hundreds
- Multiply, using the known fact. 8 hundreds × 7 = 56 hundreds, because 8 × 7 = 56.8 × 7 = 56, so 8 hundreds × 7 = 56 hundreds
- Change 56 hundreds back to a number. 1 hundred is 100, so 56 hundreds is 56 × 100. 56 hundreds = 5,600
- Write the answer. 800 × 7 = 5,600
Check. Divide back: 5,600 ÷ 7 = 800. ✓
Watch out. The answer is 56 hundreds, which has 2 zeros on the end. Count the zeros carefully.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 56 ÷ 7 = 8, and place value. 560 is 56 tens, so the answer is 8 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.56 ÷ 7 = 8
- Say the big number in tens. 560 is 56 tens.560 = 56 tens
- Divide, using the known fact. 56 tens ÷ 7 = 8 tens, because 56 ÷ 7 = 8.56 ÷ 7 = 8, so 56 tens ÷ 7 = 8 tens
- Change 8 tens back to a number. Put the zeros back.8 tens = 80
- Write the answer. 560 ÷ 7 = 80
Check. Multiply back: 80 × 7 = 560. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 56 ÷ 8 = 7, and place value. 560 is 56 tens, so the answer is 7 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.56 ÷ 8 = 7
- Say the big number in tens. 560 is 56 tens.560 = 56 tens
- Divide, using the known fact. 56 tens ÷ 8 = 7 tens, because 56 ÷ 8 = 7.56 ÷ 8 = 7, so 56 tens ÷ 8 = 7 tens
- Change 7 tens back to a number. Put the zeros back.7 tens = 70
- Write the answer. 560 ÷ 8 = 70
Check. Multiply back: 70 × 8 = 560. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 56 ÷ 8 = 7, and place value. 5,600 is 56 hundreds, so the answer is 7 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.56 ÷ 8 = 7
- Say the big number in hundreds. 5,600 is 56 hundreds.5,600 = 56 hundreds
- Divide, using the known fact. 56 hundreds ÷ 8 = 7 hundreds, because 56 ÷ 8 = 7.56 ÷ 8 = 7, so 56 hundreds ÷ 8 = 7 hundreds
- Change 7 hundreds back to a number. Put the zeros back.7 hundreds = 700
- Write the answer. 5,600 ÷ 8 = 700
Check. Multiply back: 700 × 8 = 5,600. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 3 × 8 = 24, and place value. 30 is 3 tens, so the answer is 24 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.3 × 8 = 24
- Say the bigger number in tens. 30 is 3 tens.30 = 3 tens
- Multiply, using the known fact. 3 tens × 8 = 24 tens, because 3 × 8 = 24.3 × 8 = 24, so 3 tens × 8 = 24 tens
- Change 24 tens back to a number. 1 ten is 10, so 24 tens is 24 × 10. 24 tens = 240
- Write the answer. 30 × 8 = 240
Check. Divide back: 240 ÷ 8 = 30. ✓
Watch out. The answer is 24 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 7 × 5 = 35, and place value. 50 is 5 tens, so the answer is 35 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.7 × 5 = 35
- Say the bigger number in tens. 50 is 5 tens.50 = 5 tens
- Multiply, using the known fact. 5 tens × 7 = 35 tens, because 5 × 7 = 35.5 × 7 = 35, so 5 tens × 7 = 35 tens
- Change 35 tens back to a number. 1 ten is 10, so 35 tens is 35 × 10. 35 tens = 350
- Write the answer. 7 × 50 = 350
Check. Divide back: 350 ÷ 50 = 7. ✓
Watch out. The answer is 35 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 9 × 6 = 54, and place value. 90 is 9 tens, so the answer is 54 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.9 × 6 = 54
- Say the bigger number in tens. 90 is 9 tens.90 = 9 tens
- Multiply, using the known fact. 9 tens × 6 = 54 tens, because 9 × 6 = 54.9 × 6 = 54, so 9 tens × 6 = 54 tens
- Change 54 tens back to a number. 1 ten is 10, so 54 tens is 54 × 10. 54 tens = 540
- Write the answer. 90 × 6 = 540
Check. Divide back: 540 ÷ 6 = 90. ✓
Watch out. The answer is 54 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 4 × 7 = 28, and place value. 700 is 7 hundreds, so the answer is 28 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.4 × 7 = 28
- Say the bigger number in hundreds. 700 is 7 hundreds.700 = 7 hundreds
- Multiply, using the known fact. 7 hundreds × 4 = 28 hundreds, because 7 × 4 = 28.7 × 4 = 28, so 7 hundreds × 4 = 28 hundreds
- Change 28 hundreds back to a number. 1 hundred is 100, so 28 hundreds is 28 × 100. 28 hundreds = 2,800
- Write the answer. 4 × 700 = 2,800
Check. Divide back: 2,800 ÷ 700 = 4. ✓
Watch out. The answer is 28 hundreds, which has 2 zeros on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 11 × 3 = 33, and place value. 110 is 11 tens, so the answer is 33 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.11 × 3 = 33
- Say the bigger number in tens. 110 is 11 tens.110 = 11 tens
- Multiply, using the known fact. 11 tens × 3 = 33 tens, because 11 × 3 = 33.11 × 3 = 33, so 11 tens × 3 = 33 tens
- Change 33 tens back to a number. 1 ten is 10, so 33 tens is 33 × 10. 33 tens = 330
- Write the answer. 110 × 3 = 330
Check. Divide back: 330 ÷ 3 = 110. ✓
Watch out. The answer is 33 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 8 × 9 = 72, and place value. 90 is 9 tens, so the answer is 72 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.8 × 9 = 72
- Say the bigger number in tens. 90 is 9 tens.90 = 9 tens
- Multiply, using the known fact. 9 tens × 8 = 72 tens, because 9 × 8 = 72.9 × 8 = 72, so 9 tens × 8 = 72 tens
- Change 72 tens back to a number. 1 ten is 10, so 72 tens is 72 × 10. 72 tens = 720
- Write the answer. 8 × 90 = 720
Check. Divide back: 720 ÷ 90 = 8. ✓
Watch out. The answer is 72 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 36 ÷ 6 = 6, and place value. 360 is 36 tens, so the answer is 6 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.36 ÷ 6 = 6
- Say the big number in tens. 360 is 36 tens.360 = 36 tens
- Divide, using the known fact. 36 tens ÷ 6 = 6 tens, because 36 ÷ 6 = 6.36 ÷ 6 = 6, so 36 tens ÷ 6 = 6 tens
- Change 6 tens back to a number. Put the zeros back.6 tens = 60
- Write the answer. 360 ÷ 6 = 60
Check. Multiply back: 60 × 6 = 360. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 48 ÷ 8 = 6, and place value. 480 is 48 tens, so the answer is 6 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.48 ÷ 8 = 6
- Say the big number in tens. 480 is 48 tens.480 = 48 tens
- Divide, using the known fact. 48 tens ÷ 8 = 6 tens, because 48 ÷ 8 = 6.48 ÷ 8 = 6, so 48 tens ÷ 8 = 6 tens
- Change 6 tens back to a number. Put the zeros back.6 tens = 60
- Write the answer. 480 ÷ 8 = 60
Check. Multiply back: 60 × 8 = 480. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 21 ÷ 7 = 3, and place value. 2,100 is 21 hundreds, so the answer is 3 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.21 ÷ 7 = 3
- Say the big number in hundreds. 2,100 is 21 hundreds.2,100 = 21 hundreds
- Divide, using the known fact. 21 hundreds ÷ 7 = 3 hundreds, because 21 ÷ 7 = 3.21 ÷ 7 = 3, so 21 hundreds ÷ 7 = 3 hundreds
- Change 3 hundreds back to a number. Put the zeros back.3 hundreds = 300
- Write the answer. 2,100 ÷ 7 = 300
Check. Multiply back: 300 × 7 = 2,100. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 54 ÷ 9 = 6, and place value. 5,400 is 54 hundreds, so the answer is 6 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.54 ÷ 9 = 6
- Say the big number in hundreds. 5,400 is 54 hundreds.5,400 = 54 hundreds
- Divide, using the known fact. 54 hundreds ÷ 9 = 6 hundreds, because 54 ÷ 9 = 6.54 ÷ 9 = 6, so 54 hundreds ÷ 9 = 6 hundreds
- Change 6 hundreds back to a number. Put the zeros back.6 hundreds = 600
- Write the answer. 5,400 ÷ 9 = 600
Check. Multiply back: 600 × 9 = 5,400. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 88 ÷ 11 = 8, and place value. 880 is 88 tens, so the answer is 8 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.88 ÷ 11 = 8
- Say the big number in tens. 880 is 88 tens.880 = 88 tens
- Divide, using the known fact. 88 tens ÷ 11 = 8 tens, because 88 ÷ 11 = 8.88 ÷ 11 = 8, so 88 tens ÷ 11 = 8 tens
- Change 8 tens back to a number. Put the zeros back.8 tens = 80
- Write the answer. 880 ÷ 11 = 80
Check. Multiply back: 80 × 11 = 880. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A known fact is a fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 12 ÷ 12 = 1, and place value. 1,200 is 12 hundreds, so the answer is 1 hundreds.
- Spot the fact you know. Take away the zeros and look at the digits that are left.12 ÷ 12 = 1
- Say the big number in hundreds. 1,200 is 12 hundreds.1,200 = 12 hundreds
- Divide, using the known fact. 12 hundreds ÷ 12 = 1 hundreds, because 12 ÷ 12 = 1.12 ÷ 12 = 1, so 12 hundreds ÷ 12 = 1 hundreds
- Change 1 hundreds back to a number. Put the zeros back.1 hundreds = 100
- Write the answer. 1,200 ÷ 12 = 100
Check. Multiply back: 100 × 12 = 1,200. ✓
Watch out. Keep the zeros. 420 ÷ 7 is 60, not 6.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 6 is one more than 5, so add one more group of 8 to the answer to 5 × 8.
- Write the fact you know. We start from the fact we know.5 × 8 = 40
- Compare 6 with 5. 6 is one more than 5, so we need one more group of 8.6 = 5 + 1
- Add one more group. One group is 8.40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 8 = 6. ✓
Watch out. Add 8, the size of one group, not 6 or 1.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 4 is one less than 5, so take away one group of 8 from the answer to 5 × 8.
- Write the fact you know. We start from the fact we know.5 × 8 = 40
- Compare 4 with 5. 4 is one less than 5, so we need one group of 8 fewer.4 = 5 − 1
- Take away one group. One group is 8.40 − 8 = 32
- Write the answer. 4 × 8 = 32
Check. Check by dividing: 32 ÷ 8 = 4. ✓
Watch out. Take away 8, the size of one group, not 4 or 1.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 10 is double 5, so double the answer to 5 × 8.
- Write the fact you know. We start from the fact we know.5 × 8 = 40
- Compare 10 with 5. 10 is double 5, so 10 groups of 8 are double 5 groups of 8.10 = 2 × 5
- Double the known answer. double 40 = 80
- Write the answer. 10 × 8 = 80
Check. Check by dividing: 80 ÷ 8 = 10. ✓
Watch out. Doubling the number of groups doubles the total. Do not double the other number as well.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 6 is double 3, so double the answer to 3 × 9.
- Write the fact you know. We start from the fact we know.3 × 9 = 27
- Compare 6 with 3. 6 is double 3, so 6 groups of 9 are double 3 groups of 9.6 = 2 × 3
- Double the known answer. double 20 = 40, double 7 = 14, so 40 + 14 = 54
- Write the answer. 6 × 9 = 54
Check. Check by dividing: 54 ÷ 9 = 6. ✓
Watch out. Doubling the number of groups doubles the total. Do not double the other number as well.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 6 is half of 12, so halve the answer to 12 × 5.
- Write the fact you know. We start from the fact we know.12 × 5 = 60
- Compare 6 with 12. 6 is half of 12, so 6 groups of 5 are half of 12 groups of 5.6 = 12 ÷ 2
- Halve the known answer. half of 60 = 30
- Write the answer. 6 × 5 = 30
Check. Check by dividing: 30 ÷ 5 = 6. ✓
Watch out. Halving the number of groups halves the total.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 8 is double 4, so double the answer to 4 × 7.
- Write the fact you know. We start from the fact we know.4 × 7 = 28
- Compare 8 with 4. 8 is double 4, so 8 groups of 7 are double 4 groups of 7.8 = 2 × 4
- Double the known answer. double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 8 × 7 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Doubling the number of groups doubles the total. Do not double the other number as well.
Key words. A derived fact is a new fact you work out from a fact you already know.
Method. 6 is half of 12, so halve the answer to 12 × 6.
- Write the fact you know. We start from the fact we know.12 × 6 = 72
- Compare 6 with 12. 6 is half of 12, so 6 groups of 6 are half of 12 groups of 6.6 = 12 ÷ 2
- Halve the known answer. half of 60 = 30, half of 12 = 6, so 30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Halving the number of groups halves the total.
Method. There are 8 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 8 equal bars show 8 equal groups. Each bar is 60p. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.8 × 60p
- Work it out. Use a times table trick.6 × 8 = 48
60 is 6 tens, so 8 × 6 tens = 48 tens = 480 - Write the answer. Include the unit.480p
Check. Divide back: 480 ÷ 8 = 60. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. There are 6 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 6 equal bars show 6 equal buses. Each bar is 70. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.6 × 70
- Work it out. Use a times table trick.6 × 7 = 42
70 is 7 tens, so 6 × 7 tens = 42 tens = 420 - Write the answer. Include the unit.420 passengers
Check. Divide back: 420 ÷ 6 = 70. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 540. Each bar is 9. We want to know how many bars. (The picture shows only some of the bars.)
- Choose the operation. We want to know how many groups of 9 fit into 540. That is a division.540 ÷ 9
- Use the times tables. Think: what do we multiply 9 by to get 540?54 ÷ 9 = 6
540 is 54 tens, so 54 tens ÷ 9 = 6 tens = 60 - Write the answer. Include the unit.60 boxes
Check. Multiply back: 60 × 9 = 540. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. Check Zoe’s answer. She used the right fact, but what has happened to the zero?
- Zoe’s fact. 6 × 7 = 42 is correct.6 × 7 = 42
- Look at 60. 60 is not 6. It is 6 tens, so the answer is 42 tens, not 42 ones.6 tens × 7 = 42 tens
- Write 42 tens as a number. 42 tens = 42 × 10.42 tens = 420
- Answer. 60 × 7 = 420
Check. Estimate: 60 × 7 is about 60 × 10 = 600, so the answer must be about 600, not 42. ✓
Watch out. Zoe forgot the zero. Always put the zeros back at the end.
Method. Work out each one. The odd one out has a different answer from the others.
- Work out A and B. Use 6 × 7 = 42 and put the zero back.6 × 70 = 420 60 × 7 = 420
- Work out C. Multiplying by 10 moves the digits one place left.42 × 10 = 420
- Work out D. 600 is 6 hundreds, so the answer is 42 hundreds.600 × 7 = 4,200
- Choose the odd one out. A, B and C are all 420.D
Check. 4,200 ÷ 7 = 600. ✓
Watch out. Count the zeros: A, B and C each have one zero in total in the numbers multiplied. D has two.
Method. A multiple of 10 is a number of tens. Think about what happens to the ones digit.
- Try some examples. Pick different multiples of 10.30 × 7 = 210 50 × 3 = 150 80 × 9 = 720
- Explain why. A multiple of 10 is a number of tens. A number of tens times a whole number is still a number of tens, and tens have 0 ones.So the ones digit is always 0.
- Decide. Always
Check. Check with an odd times: 70 × 5 = 350. It ends in 0. ✓
Watch out. This does not work the other way. Not every number that ends in 0 is a multiple of 10 times a fact you know, but they are all multiples of 10.
Method. 5,600 is 56 hundreds. So use 56 as a fact, then change the units to hundreds.
- Write the fact you know. 7 × 8 = 56
- Say 5,600 in hundreds. 5,600 is 56 hundreds.5,600 = 56 hundreds
- Write four facts. The hundreds go with one of the numbers each time.700 × 8 = 5,600
8 × 700 = 5,600
5,600 ÷ 8 = 700
5,600 ÷ 7 = 800
Check. Check one: 700 × 8 = 7 hundreds × 8 = 56 hundreds = 5,600. ✓
Watch out. There are more answers too, such as 800 × 7 = 5,600. Any correct fact is fine.
Exercise 3H Multiplication and division problems
Non-calculatorMethod. There are 7 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 7 equal bars show 7 equal years. Each bar is 12. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.7 × 12
- Work it out. Use a times table trick.10 × 7 = 70
7 + 7 = 14
70 + 14 = 84
7 × 12 = 84 - Write the answer. Include the unit.84 months
Check. Divide back: 84 ÷ 7 = 12. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 60. It is split into 5 equal parts. We want the size of one part.
- Choose the operation. Sharing equally means dividing.60 ÷ 5
- Use the times tables. Think: what do we multiply 5 by to get 60?12 × 5 = 60, so 60 ÷ 5 = 12
- Write the answer. Include the unit.12 stickers
Check. Multiply back: 12 × 5 = 60. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. There are 12 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 12 equal bars show 12 equal books. Each bar is £8. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.12 × £8
- Work it out. Use a times table trick.10 × 8 = 80
8 + 8 = 16
80 + 16 = 96
12 × 8 = 96 - Write the answer. Include the unit.£96
Check. Divide back: 96 ÷ 12 = 8. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 99. Each bar is 9. We want to know how many bars. (The picture shows only some of the bars.)
- Choose the operation. We want to know how many groups of 9 fit into 99. That is a division.99 ÷ 9
- Use the times tables. Think: what do we multiply 9 by to get 99?11 × 9 = 99, so 99 ÷ 9 = 11
- Write the answer. Include the unit.11 pots
Check. Multiply back: 11 × 9 = 99. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Method. Two steps. First multiply to find how many stickers Aisha has. Then take away the stickers she gives away.
- Draw a bar model for step 1. 4 equal packs of 12 stickers.
- Step 1: multiply. Equal groups, so multiply.double 10 = 20, double 2 = 4, so 20 + 4 = 24
double 20 = 40, double 4 = 8, so 40 + 8 = 48
4 × 12 = 48 - Step 2: take away. Aisha gives away 15. Take away 10, then 5.48 − 10 = 38, then 38 − 5 = 33
- Write the answer. 33 stickers
Check. Add back: 33 + 15 = 48 and 48 ÷ 4 = 12. ✓
Watch out. Do both steps. 48 is the number she starts with, not the number she has left.
Method. Two steps. First find the total cost of the cakes. Then take it away from the money Leo pays with to find the change.
- Step 1: multiply. 7 cakes at £6 each.5 × 7 = 35
35 + 7 = 42
7 × 6 = 42 - Step 2: find the change. Change = money paid − cost.£50 − £42: 42 + 8 = 50, so the change is £8
- Write the answer. £8
Check. Add up: £42 + £8 = £50. ✓
Watch out. The change is what is left, not the cost of the cakes.
Method. There are two kinds of box, so work out the markers in each kind and add the two totals.
- Boxes of 8 markers. 5 boxes of 8.10 × 8 = 80
half of 80 = 40
5 × 8 = 40 - Boxes of 12 markers. 3 boxes of 12.double 10 = 20, double 2 = 4, so 20 + 4 = 24
24 + 12 = 36
3 × 12 = 36 - Add the two totals. 40 + 36 = 76
- Write the answer. 76 markers
Check. Take away one total: 76 − 40 = 36. ✓
Watch out. Do not multiply all four numbers together. Multiply in pairs and then add.
Method. Work out how many pages each child reads, then compare the two totals.
- Mei’s pages. 7 pages a day for 12 days.10 × 7 = 70
7 + 7 = 14
70 + 14 = 84
7 × 12 = 84 - Ben’s pages. 9 pages a day for 9 days.10 × 9 = 90
90 − 9 = 81
9 × 9 = 81 - Compare. Find the difference between 84 and 81.84 − 81 = 3
- Write the answer. Mei reads 3 more pages.
Check. 81 + 3 = 84. ✓
Watch out. The question asks “how many more”, so you need the difference, not just who reads more.
| Cards | Price of one pack |
|---|---|
| Football | £4 |
| Animals | £7 |
Sam buys 8 packs of football cards and 6 packs of animal cards. How much does he spend?
Method. Work out the cost of each kind of cards, then add.
- Football cards. 8 packs at £4 each.8 + 8 = 16
double 10 = 20, double 6 = 12, so 20 + 12 = 32
8 × 4 = 32 - Animal cards. 6 packs at £7 each.5 × 7 = 35
35 + 7 = 42
6 × 7 = 42 - Add the two costs. £32 + £42 = £74
- Write the answer. £74
Check. £74 − £32 = £42. ✓
Watch out. Multiply first, then add. Do not add the prices first.
Method. Look at how many bars each model has and what each bar shows.
- Read the question. 9 rows, and each row has 7 seats. So there are 9 equal groups of 7.Model should have 9 bars of 7.
- Choose the model. Model A has 9 bars labelled 7. Model B has 7 bars labelled 9.Model A matches.
- Work out both totals. Multiplication can be done in either order.9 × 7 = 63 and 7 × 9 = 63
- Answer the question. Yes. Both are 63 because 9 × 7 = 7 × 9.
Check. Turn the seats on their side: 7 rows of 9 seats is the same seats. ✓
Watch out. The models are different pictures of different groups, but they have the same total.
Method. Work out both. Then show why they must be the same with an array.
- Work out 8 packs of 6. Double three times.6 + 6 = 12
double 10 = 20, double 2 = 4, so 20 + 4 = 24
double 20 = 40, double 4 = 8, so 40 + 8 = 48
8 × 6 = 48 - Work out 6 packs of 8. This is the same two numbers the other way round.6 + 6 = 12
double 10 = 20, double 2 = 4, so 20 + 4 = 24
double 20 = 40, double 4 = 8, so 40 + 8 = 48
6 × 8 = 48 - Use the arrays to explain. Turning the first array on its side gives the second array. No dots are added or lost.8 × 6 = 6 × 8 = 48
- Answer. Yes, Anil is right.
Check. 48 ÷ 6 = 8 and 48 ÷ 8 = 6. ✓
Watch out. This is commutativity. It works for any two numbers that are multiplied.
A 6 bags have 9 apples in each bag. How many apples are there?
B 42 pens are shared equally between 6 children. How many pens does each child get?
C A rope 56 m long is cut into pieces that are each 7 m long. How many pieces are there?
D A train has 8 carriages with 12 seats in each carriage. How many seats are there?
Method. For each problem, ask: do I know the total? If the total is known and I need to share it or split it, divide. If I know the size of each group and the number of groups, multiply.
- Problem A. 6 groups of 9 and the total is not known.Multiply: 6 × 9
- Problem B. The total, 42, is shared equally between 6.Divide: 42 ÷ 6
- Problem C. The total length, 56 m, is split into pieces of 7 m. How many fit?Divide: 56 ÷ 7
- Problem D. 8 groups of 12 and the total is not known.Multiply: 8 × 12
- Choose. B and C
Check. 42 ÷ 6 = 7 and 56 ÷ 7 = 8. Both are easy to check by multiplying. ✓
Watch out. Do not choose by looking for one word. “Shared” and “cut into” both mean divide here.
Method. Try different numbers of cows. For each try, work out the number of chickens (10 minus the cows) and count all the legs.
- Make a table. Chickens = 10 − cows. Legs = 2 × chickens + 4 × cows.
Chickens Cows Chicken legs Cow legs Total legs 8 2 16 8 24 7 3 14 12 26 6 4 12 16 28 5 5 10 20 30 - Look at the totals. We want exactly 28 legs. Too few legs means we need more cows.With 4 cows: 6 chickens have 12 legs, 4 cows have 16 legs. 12 + 16 = 28.
- Write the answer. 6 chickens and 4 cows
Check. 6 + 4 = 10 animals. 6 × 2 = 12 and 4 × 4 = 16. 12 + 16 = 28 legs. ✓
Watch out. Check both facts: the number of animals and the number of legs.
Exercise 3I Times tables check practice: 25 questions, 6 seconds each
Non-calculatorMethod. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 2 = 2 × 9. Use the 2 times table trick.9 × 2 = 2 × 9
- Double the number. Doubling means adding the number to itself.9 + 9 = 18
- Write the answer. 9 × 2 = 18
Check. The digits of 18 add up to 9: 1 + 8 = 9. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 4 = 40
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 40 = 20
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 4 = 20
Check. Check by dividing: 20 ÷ 4 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.3 + 3 = 6
- Add one more group. 3 = 2 + 1, so add the number once more.6 + 3 = 9
- Write the answer. 3 × 3 = 9
Check. Check by dividing: 9 ÷ 3 = 3. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 11 = 11 × 4. Use the 11 times table trick.4 × 11 = 11 × 4
- Multiply by 10. 10 lots of the number first.10 × 4 = 40
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 44.40 + 4 = 44
- Write the answer. 4 × 11 = 44
Check. Check by dividing: 44 ÷ 4 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 11 × 2 = 2 × 11. Use the 2 times table trick.11 × 2 = 2 × 11
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 1 = 2, so 20 + 2 = 22
- Write the answer. 11 × 2 = 22
Check. Check by dividing: 22 ÷ 2 = 11. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 5 = 5 × 3. Use the 5 times table trick.3 × 5 = 5 × 3
- Multiply by 10. This is easy: move the digits one place to the left.10 × 3 = 30
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 20 = 10, half of 10 = 5, so 10 + 5 = 15
- Write the answer. Answers in the 5 times table end in 0 or 5.3 × 5 = 15
Check. Check by dividing: 15 ÷ 3 = 5. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 5 means 5 lots of 10, which is 5 tens.5 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.5 → 50
- Write the answer. 10 × 5 = 50
Check. Check by dividing: 50 ÷ 5 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 10 = 10 × 3. Use the 10 times table trick.3 × 10 = 10 × 3
- Think about tens. 10 × 3 means 3 lots of 10, which is 3 tens.3 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.3 → 30
- Write the answer. 3 × 10 = 30
Check. Check by dividing: 30 ÷ 3 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 5 = 5 × 7. Use the 5 times table trick.7 × 5 = 5 × 7
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.7 × 5 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 4 = 4 × 8. Use the 4 times table trick.8 × 4 = 4 × 8
- Double the number. This gives 2 lots.8 + 8 = 16
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 6 = 12, so 20 + 12 = 32
- Write the answer. 8 × 4 = 32
Check. Check by dividing: 32 ÷ 4 = 8. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 11 = 110
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 100 = 50, half of 10 = 5, so 50 + 5 = 55
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 11 = 55
Check. Check by dividing: 55 ÷ 5 = 11. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 11 means 11 lots of 10, which is 11 tens.11 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.11 → 110
- Write the answer. 10 × 11 = 110
Check. Check by dividing: 110 ÷ 10 = 11. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 2 = 2 × 4. Use the 2 times table trick.4 × 2 = 2 × 4
- Double the number. Doubling means adding the number to itself.4 + 4 = 8
- Write the answer. 4 × 2 = 8
Check. Check by dividing: 8 ÷ 2 = 4. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 3 × 4 = 4 × 3. Use the 4 times table trick.3 × 4 = 4 × 3
- Double the number. This gives 2 lots.3 + 3 = 6
- Double the answer again. Doubling twice gives 4 lots.6 + 6 = 12
- Write the answer. 3 × 4 = 12
Check. Check by dividing: 12 ÷ 3 = 4. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.5 + 5 = 10
- Write the answer. 2 × 5 = 10
Check. Check by dividing: 10 ÷ 2 = 5. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 9 means 9 lots of 10, which is 9 tens.9 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.9 → 90
- Write the answer. 10 × 9 = 90
Check. The digits of 90 add up to 9: 9 + 0 = 9. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 3 × 7 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Take away one group. 9 = 10 − 1, so take away the number itself once.30 − 3 = 27
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 3 = 27
Check. The digits of 27 add up to 9: 2 + 7 = 9. ✓
Watch out. Take away 3, the other number, not 9. For 9 × 3 you work out 10 × 3 − 3.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 4 = 4 × 6. Use the 4 times table trick.6 × 4 = 4 × 6
- Double the number. This gives 2 lots.6 + 6 = 12
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 6 × 4 = 24
Check. Check by dividing: 24 ÷ 4 = 6. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 9 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 33.30 + 3 = 33
- Write the answer. 11 × 3 = 33
Check. Check by dividing: 33 ÷ 3 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.4 + 4 = 8
- Double the answer again. Doubling twice gives 4 lots.8 + 8 = 16
- Write the answer. 4 × 4 = 16
Check. Check by dividing: 16 ÷ 4 = 4. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 10 = 10 × 12. Use the 10 times table trick.12 × 10 = 10 × 12
- Think about tens. 10 × 12 means 12 lots of 10, which is 12 tens.12 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.12 → 120
- Write the answer. 12 × 10 = 120
Check. Check by dividing: 120 ÷ 10 = 12. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 11 = 11 × 8. Use the 11 times table trick.8 × 11 = 11 × 8
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 88.80 + 8 = 88
- Write the answer. 8 × 11 = 88
Check. Check by dividing: 88 ÷ 8 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 4 × 12 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 3 × 7 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 9 = 90
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 99.90 + 9 = 99
- Write the answer. 11 × 9 = 99
Check. The digits of 99 add up to 9: 9 + 9 = 18. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 10 = 10 × 8. Use the 10 times table trick.8 × 10 = 10 × 8
- Think about tens. 10 × 8 means 8 lots of 10, which is 8 tens.8 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.8 → 80
- Write the answer. 8 × 10 = 80
Check. Check by dividing: 80 ÷ 8 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.8 + 8 = 16
- Write the answer. 2 × 8 = 16
Check. Check by dividing: 16 ÷ 2 = 8. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.3 + 3 = 6
- Write the answer. 2 × 3 = 6
Check. Check by dividing: 6 ÷ 2 = 3. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 9 means 9 lots of 10, which is 9 tens.9 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.9 → 90
- Write the answer. 10 × 9 = 90
Check. The digits of 90 add up to 9: 9 + 0 = 9. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 77.70 + 7 = 77
- Write the answer. 11 × 7 = 77
Check. Check by dividing: 77 ÷ 7 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 5 × 10 = 10 × 5. Use the 10 times table trick.5 × 10 = 10 × 5
- Think about tens. 10 × 5 means 5 lots of 10, which is 5 tens.5 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.5 → 50
- Write the answer. 5 × 10 = 50
Check. Check by dividing: 50 ÷ 5 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 9 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Seven is five and two. Work out 5 lots and 2 lots, then add them.
- Work out 5 lots. The 5 times table is half of the 10 times table.5 × 7 = 35
- Work out 2 lots. Double the number.7 + 7 = 14
- Add them. 7 = 5 + 2.35 + 14 = 49
- Write the answer. 7 × 7 = 49
Check. Check by dividing: 49 ÷ 7 = 7. ✓
Watch out. Do not forget the 2 lots. 7 lots = 5 lots + 2 lots.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Think about tens. 10 × 11 means 11 lots of 10, which is 11 tens.11 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.11 → 110
- Write the answer. 10 × 11 = 110
Check. Check by dividing: 110 ÷ 10 = 11. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.5 + 5 = 10
- Write the answer. 2 × 5 = 10
Check. Check by dividing: 10 ÷ 2 = 5. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 88.80 + 8 = 88
- Write the answer. 11 × 8 = 88
Check. Check by dividing: 88 ÷ 8 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 3 = 3 × 6. Use the 3 times table trick.6 × 3 = 3 × 6
- Double the number. This gives 2 lots.6 + 6 = 12
- Add one more group. 3 = 2 + 1, so add the number once more.12 + 6 = 18
- Write the answer. 6 × 3 = 18
Check. Check by dividing: 18 ÷ 3 = 6. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 5 = 5 × 7. Use the 5 times table trick.7 × 5 = 5 × 7
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.7 × 5 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.8 + 8 = 16
- Add one more group. 3 = 2 + 1, so add the number once more.16 + 8 = 24
- Write the answer. 3 × 8 = 24
Check. Check by dividing: 24 ÷ 3 = 8. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 12 × 6 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 6 × 7 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 2 = 2 × 9. Use the 2 times table trick.9 × 2 = 2 × 9
- Double the number. Doubling means adding the number to itself.9 + 9 = 18
- Write the answer. 9 × 2 = 18
Check. The digits of 18 add up to 9: 1 + 8 = 9. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 8 × 6 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 33.30 + 3 = 33
- Write the answer. 11 × 3 = 33
Check. Check by dividing: 33 ÷ 3 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 5 = 5 × 8. Use the 5 times table trick.8 × 5 = 5 × 8
- Multiply by 10. This is easy: move the digits one place to the left.10 × 8 = 80
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40
- Write the answer. Answers in the 5 times table end in 0 or 5.8 × 5 = 40
Check. Check by dividing: 40 ÷ 5 = 8. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 4 = 4 × 9. Use the 4 times table trick.9 × 4 = 4 × 9
- Double the number. This gives 2 lots.9 + 9 = 18
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 8 = 16, so 20 + 16 = 36
- Write the answer. 9 × 4 = 36
Check. The digits of 36 add up to 9: 3 + 6 = 9. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 4 × 10 = 10 × 4. Use the 10 times table trick.4 × 10 = 10 × 4
- Think about tens. 10 × 4 means 4 lots of 10, which is 4 tens.4 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.4 → 40
- Write the answer. 4 × 10 = 40
Check. Check by dividing: 40 ÷ 4 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Three is double and one more. Double the number, then add the number once.
- Double the number. This gives 2 lots.3 + 3 = 6
- Add one more group. 3 = 2 + 1, so add the number once more.6 + 3 = 9
- Write the answer. 3 × 3 = 9
Check. Check by dividing: 9 ÷ 3 = 3. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Three is double and one more. Double the number, then add the number once.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 3 = 3 × 7. Use the 3 times table trick.7 × 3 = 3 × 7
- Double the number. This gives 2 lots.7 + 7 = 14
- Add one more group. 3 = 2 + 1, so add the number once more.14 + 7 = 21
- Write the answer. 7 × 3 = 21
Check. Check by dividing: 21 ÷ 3 = 7. ✓
Watch out. Add the number itself, not 3, as the extra group.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.9 + 9 = 18
- Write the answer. 2 × 9 = 18
Check. The digits of 18 add up to 9: 1 + 8 = 9. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 2 = 2 × 8. Use the 2 times table trick.8 × 2 = 2 × 8
- Double the number. Doubling means adding the number to itself.8 + 8 = 16
- Write the answer. 8 × 2 = 16
Check. Check by dividing: 16 ÷ 2 = 8. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 6 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 6 = 60
- Multiply by 2. Double the number.6 + 6 = 12
- Add the two answers together. 12 = 10 + 2.60 + 12 = 72
- Write the answer. 12 × 6 = 72
Check. Check by dividing: 72 ÷ 6 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 7 = 70
- Multiply by 2. Double the number.7 + 7 = 14
- Add the two answers together. 12 = 10 + 2.70 + 14 = 84
- Write the answer. 12 × 7 = 84
Check. Check by dividing: 84 ÷ 7 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 10 = 10 × 7. Use the 10 times table trick.7 × 10 = 10 × 7
- Think about tens. 10 × 7 means 7 lots of 10, which is 7 tens.7 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.7 → 70
- Write the answer. 7 × 10 = 70
Check. Check by dividing: 70 ÷ 7 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 70 halved.5 × 7 = 35
- Add one more group. 6 = 5 + 1, so add the number once more.35 + 7 = 42
- Write the answer. 6 × 7 = 42
Check. Check by dividing: 42 ÷ 6 = 7. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 8 = 8 × 6. Use the 8 times table trick.6 × 8 = 8 × 6
- Double once. This gives 2 lots.6 + 6 = 12
- Double again. This gives 4 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double a third time. This gives 8 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 6 × 8 = 48
Check. Check by dividing: 48 ÷ 6 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 11 = 11 × 12. Use the 11 times table trick.12 × 11 = 11 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Add one more group. 11 = 10 + 1, so add the number itself once more.120 + 12 = 132
- Write the answer. 12 × 11 = 132
Check. Check by dividing: 132 ÷ 11 = 12. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 12 = 120
- Multiply by 2. Double the number.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Add the two answers together. 12 = 10 + 2.120 + 24 = 144
- Write the answer. 12 × 12 = 144
Check. Check by dividing: 144 ÷ 12 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Eleven is ten and one more. Multiply by 10, then add one more group.
- Multiply by 10. 10 lots of the number first.10 × 8 = 80
- Add one more group. 11 = 10 + 1, so add the number itself once more. You can also write the digit twice: 88.80 + 8 = 88
- Write the answer. 11 × 8 = 88
Check. Check by dividing: 88 ÷ 8 = 11. ✓
Watch out. The “write the digit twice” trick only works from 11 × 1 to 11 × 9. For 11 × 12 it does not give 1212. Use 10 lots + 1 lot.
Method. To multiply by 10, every digit moves one place to the left. The ones become tens.
- Swap the numbers round. Order does not matter in multiplication, so 8 × 10 = 10 × 8. Use the 10 times table trick.8 × 10 = 10 × 8
- Think about tens. 10 × 8 means 8 lots of 10, which is 8 tens.8 tens
- Move the digits one place to the left. A tens column needs a 0 in the ones place.8 → 80
- Write the answer. 8 × 10 = 80
Check. Check by dividing: 80 ÷ 8 = 10. ✓
Watch out. The 10 times table has a 0 in the ones place every time. Put the 0 on the end, but think “tens” so you understand why.
Method. Four is double double. Double the number, then double the answer.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 4 = 4 × 12. Use the 4 times table trick.12 × 4 = 4 × 12
- Double the number. This gives 2 lots.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Double the answer again. Doubling twice gives 4 lots.double 20 = 40, double 4 = 8, so 40 + 8 = 48
- Write the answer. 12 × 4 = 48
Check. Check by dividing: 48 ÷ 4 = 12. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Twelve is ten and two. Multiply by 10, multiply by 2, then add.
- Multiply by 10. Move the digits one place to the left.10 × 8 = 80
- Multiply by 2. Double the number.8 + 8 = 16
- Add the two answers together. 12 = 10 + 2.80 + 16 = 96
- Write the answer. 12 × 8 = 96
Check. Check by dividing: 96 ÷ 8 = 12. ✓
Watch out. Do both parts, 10 lots and 2 lots, then add. Do not stop after 10 lots.
Method. Eight is double double double. Double the number three times.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 8 = 8 × 7. Use the 8 times table trick.7 × 8 = 8 × 7
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 7 × 8 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 7 × 9 = 9 × 7. Use the 9 times table trick.7 × 9 = 9 × 7
- Multiply by 10. 10 lots of the number first.10 × 7 = 70
- Take away one group. 9 = 10 − 1, so take away the number itself once.70 − 7 = 63
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).7 × 9 = 63
Check. The digits of 63 add up to 9: 6 + 3 = 9. ✓
Watch out. Take away 7, the other number, not 9. For 9 × 7 you work out 10 × 7 − 7.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 9 × 5 = 5 × 9. Use the 5 times table trick.9 × 5 = 5 × 9
- Multiply by 10. This is easy: move the digits one place to the left.10 × 9 = 90
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 80 = 40, half of 10 = 5, so 40 + 5 = 45
- Write the answer. Answers in the 5 times table end in 0 or 5.9 × 5 = 45
Check. The digits of 45 add up to 9: 4 + 5 = 9. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Multiplying by 2 is the same as doubling. Double the number.
- Double the number. Doubling means adding the number to itself.double 10 = 20, double 2 = 4, so 20 + 4 = 24
- Write the answer. 2 × 12 = 24
Check. Check by dividing: 24 ÷ 2 = 12. ✓
Watch out. Doubling is not adding 2. To double 7, add 7 + 7, not 7 + 2.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Swap the numbers round. Order does not matter in multiplication, so 12 × 9 = 9 × 12. Use the 9 times table trick.12 × 9 = 9 × 12
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Take away one group. 9 = 10 − 1, so take away the number itself once.120 − 12 = 108
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).12 × 9 = 108
Check. Check by dividing: 108 ÷ 9 = 12. ✓
Watch out. Take away 12, the other number, not 9. For 9 × 12 you work out 10 × 12 − 12.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Swap the numbers round. Order does not matter in multiplication, so 6 × 5 = 5 × 6. Use the 5 times table trick.6 × 5 = 5 × 6
- Multiply by 10. This is easy: move the digits one place to the left.10 × 6 = 60
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30
- Write the answer. Answers in the 5 times table end in 0 or 5.6 × 5 = 30
Check. Check by dividing: 30 ÷ 5 = 6. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Four is double double. Double the number, then double the answer.
- Double the number. This gives 2 lots.9 + 9 = 18
- Double the answer again. Doubling twice gives 4 lots.double 10 = 20, double 8 = 16, so 20 + 16 = 36
- Write the answer. 4 × 9 = 36
Check. The digits of 36 add up to 9: 3 + 6 = 9. ✓
Watch out. You must double twice. Doubling once gives the 2 times table.
Method. Six is five and one more. Work out 5 lots, then add one more group.
- Work out 5 lots. The 5 times table is half of the 10 times table: 60 halved.5 × 6 = 30
- Add one more group. 6 = 5 + 1, so add the number once more.30 + 6 = 36
- Write the answer. 6 × 6 = 36
Check. Check by dividing: 36 ÷ 6 = 6. ✓
Watch out. Add one more group, not six more. 6 lots = 5 lots + 1 lot.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 3 = 30
- Take away one group. 9 = 10 − 1, so take away the number itself once.30 − 3 = 27
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 3 = 27
Check. The digits of 27 add up to 9: 2 + 7 = 9. ✓
Watch out. Take away 3, the other number, not 9. For 9 × 3 you work out 10 × 3 − 3.
Method. Five is half of ten. Multiply by 10 first, then halve the answer.
- Multiply by 10. This is easy: move the digits one place to the left.10 × 7 = 70
- Halve the answer. 5 is half of 10, so 5 lots of a number is half of 10 lots.half of 60 = 30, half of 10 = 5, so 30 + 5 = 35
- Write the answer. Answers in the 5 times table end in 0 or 5.5 × 7 = 35
Check. Check by dividing: 35 ÷ 5 = 7. ✓
Watch out. Halve the answer to 10 × the number. Do not halve the number before you multiply by 10 and then forget to multiply.
Method. Use the 7 times table. Count up in 7s until you reach 56.
- Turn the division into a missing multiplication. 56 ÷ 7 asks: what do we multiply 7 by to get 56?56 ÷ 7 = ? means ? × 7 = 56
- Count up in 7s until you reach 56. Each number you say is one more group of 7.7, 14, 21, 28, 35, 42, 49, 56
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 7 = 56
- Write the answer. 56 ÷ 7 = 8
Check. Multiply back: 8 × 7 = 56. ✓
Watch out. Know your 7 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 6 is multiplied by to make 36.6 × ? = 36
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 36 by 6.36 ÷ 6 = 6
- Write the missing number. 6 × 6 = 36
Check. Put it back: 6 × 6 = 36. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 6, makes 24.? × 6 = 24
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 24 by 6.24 ÷ 6 = 4
- Write the missing number. 4 × 6 = 24
Check. Put it back: 4 × 6 = 24. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 7 gives 10.? ÷ 7 = 10
- Use the inverse (opposite) operation. The opposite of dividing by 7 is multiplying by 7.10 × 7 = 70
- Write the missing number. 70 ÷ 7 = 10
Check. Put it back: 70 ÷ 7 = 10. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 132 divided by the missing number makes 12.132 ÷ ? = 12
- Turn it into a multiplication. 12 lots of the missing number make 132.12 × ? = 132, so ? = 132 ÷ 12
- Work out the division. Count up in 12s, or use the 12 times table.132 ÷ 12 = 11
- Write the missing number. 132 ÷ 11 = 12
Check. Put it back: 132 ÷ 11 = 12. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Use the 6 times table. Count up in 6s until you reach 30.
- Turn the division into a missing multiplication. 30 ÷ 6 asks: what do we multiply 6 by to get 30?30 ÷ 6 = ? means ? × 6 = 30
- Count up in 6s until you reach 30. Each number you say is one more group of 6.6, 12, 18, 24, 30
- Count how many numbers you said. The number of jumps is the answer.I said 5 numbers, so 5 × 6 = 30
- Write the answer. 30 ÷ 6 = 5
Check. Multiply back: 5 × 6 = 30. ✓
Watch out. Know your 6 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 11 is multiplied by to make 121.11 × ? = 121
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 121 by 11.121 ÷ 11 = 11
- Write the missing number. 11 × 11 = 121
Check. Put it back: 11 × 11 = 121. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 3, makes 21.? × 3 = 21
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 21 by 3.21 ÷ 3 = 7
- Write the missing number. 7 × 3 = 21
Check. Put it back: 7 × 3 = 21. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 3 gives 10.? ÷ 3 = 10
- Use the inverse (opposite) operation. The opposite of dividing by 3 is multiplying by 3.10 × 3 = 30
- Write the missing number. 30 ÷ 3 = 10
Check. Put it back: 30 ÷ 3 = 10. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 30 divided by the missing number makes 6.30 ÷ ? = 6
- Turn it into a multiplication. 6 lots of the missing number make 30.6 × ? = 30, so ? = 30 ÷ 6
- Work out the division. Count up in 6s, or use the 6 times table.30 ÷ 6 = 5
- Write the missing number. 30 ÷ 5 = 6
Check. Put it back: 30 ÷ 5 = 6. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. Use the 11 times table. Count up in 11s until you reach 99.
- Turn the division into a missing multiplication. 99 ÷ 11 asks: what do we multiply 11 by to get 99?99 ÷ 11 = ? means ? × 11 = 99
- Count up in 11s until you reach 99. Each number you say is one more group of 11.11, 22, 33, 44, 55, 66, 77, 88, 99
- Count how many numbers you said. The number of jumps is the answer.I said 9 numbers, so 9 × 11 = 99
- Write the answer. 99 ÷ 11 = 9
Check. Multiply back: 9 × 11 = 99. ✓
Watch out. Know your 11 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 5 is multiplied by to make 40.5 × ? = 40
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 40 by 5.40 ÷ 5 = 8
- Write the missing number. 5 × 8 = 40
Check. Put it back: 5 × 8 = 40. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 8, makes 32.? × 8 = 32
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 32 by 8.32 ÷ 8 = 4
- Write the missing number. 4 × 8 = 32
Check. Put it back: 4 × 8 = 32. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 4 gives 11.? ÷ 4 = 11
- Use the inverse (opposite) operation. The opposite of dividing by 4 is multiplying by 4.11 × 4 = 44
- Write the missing number. 44 ÷ 4 = 11
Check. Put it back: 44 ÷ 4 = 11. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 77 divided by the missing number makes 11.77 ÷ ? = 11
- Turn it into a multiplication. 11 lots of the missing number make 77.11 × ? = 77, so ? = 77 ÷ 11
- Work out the division. Count up in 11s, or use the 11 times table.77 ÷ 11 = 7
- Write the missing number. 77 ÷ 7 = 11
Check. Put it back: 77 ÷ 7 = 11. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. To divide by 10, every digit moves one place to the right.
- Turn the division into a missing multiplication. 60 ÷ 10 asks: what do we multiply 10 by to get 60?60 ÷ 10 = ? means ? × 10 = 60
- Move the digits one place to the right. Tens become ones.60 → 6
- Write the answer. 60 ÷ 10 = 6
Check. Multiply back: 6 × 10 = 60. ✓
Watch out. Check that the number gets smaller. Dividing by 10 makes ten times smaller.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that 6 is multiplied by to make 36.6 × ? = 36
- Use the inverse (opposite) operation. The opposite of multiplying is dividing. Divide 36 by 6.36 ÷ 6 = 6
- Write the missing number. 6 × 6 = 36
Check. Put it back: 6 × 6 = 36. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 4, makes 16.? × 4 = 16
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 16 by 4.16 ÷ 4 = 4
- Write the missing number. 4 × 4 = 16
Check. Put it back: 4 × 4 = 16. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 6 gives 11.? ÷ 6 = 11
- Use the inverse (opposite) operation. The opposite of dividing by 6 is multiplying by 6.11 × 6 = 66
- Write the missing number. 66 ÷ 6 = 11
Check. Put it back: 66 ÷ 6 = 11. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. 120 divided by the missing number makes 12.120 ÷ ? = 12
- Turn it into a multiplication. 12 lots of the missing number make 120.12 × ? = 120, so ? = 120 ÷ 12
- Work out the division. Count up in 12s, or use the 12 times table.120 ÷ 12 = 10
- Write the missing number. 120 ÷ 10 = 12
Check. Put it back: 120 ÷ 10 = 12. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Method. There are 25 questions and 6 seconds for each. Multiply, then change the seconds into minutes and seconds.
- Multiply 25 by 6. Split 25 into 20 and 5.20 × 6 = 120 and 5 × 6 = 30, so 120 + 30 = 150 seconds
- Change to minutes and seconds. 1 minute is 60 seconds. 2 minutes is 120 seconds.150 = 120 + 30, so 150 seconds = 2 minutes 30 seconds
- Write the answer. 150 seconds = 2 minutes 30 seconds
Check. 2 minutes 30 seconds = 120 + 30 = 150 seconds. 150 ÷ 6 = 25. ✓
Watch out. There is a short rest between questions in the real check, but the 6 seconds is for answering each question.
Method. There is more than one trick for each fact. Pick two that you trust.
- Way 1: double three times. The 8 times table is double, double, double.double 7 = 14, double 14 = 28, double 28 = 56
- Way 2: use 5 lots and 2 lots. 7 = 5 + 2, so 7 lots of 8 is 5 lots of 8 plus 2 lots of 8.5 × 8 = 40 and 2 × 8 = 16, so 40 + 16 = 56
- Write the answer. Both ways give the same answer.7 × 8 = 56
Check. Also 56 ÷ 7 = 8. ✓
Watch out. A third way: 7 × 7 = 49, and 49 + 7 = 56.
Method. Look for facts that are repeated in the grid because of commutativity.
- Look at the grid. The grid is a mirror image across the diagonal (6, 49, 64, 81 and so on).For example 6 × 7 and 7 × 6 are both 42.
- Count the different facts. The 4 square facts (6 × 6, 7 × 7, 8 × 8, 9 × 9) are on the diagonal. The other 12 boxes make 6 pairs of repeats.4 + 6 = 10
- List them. 6 × 6, 6 × 7, 6 × 8, 6 × 9, 7 × 7, 7 × 8, 7 × 9, 8 × 8, 8 × 9, 9 × 9
- Answer Dev. Only 10 facts are different.
Check. 4 squares + 12 other boxes ÷ 2 = 4 + 6 = 10. ✓
Watch out. Learn both orders in your head: when you see 8 × 6, think 6 × 8.
Chapter summary
| Skill | Method |
|---|---|
| Multiplication | Equal groups: 3 × 4 = 4 + 4 + 4. An array has rows and columns. 3 × 4 = 4 × 3 (order does not matter). |
| × 0 and × 1 | Any number × 0 = 0. Any number × 1 = the same number. Any number ÷ 1 = the same number. |
| 2, 4, 8 | Double (× 2). Double double (× 4). Double three times (× 8). |
| 10 and 5 | × 10: digits move one place left. × 5: do × 10 and halve. |
| 3, 6, 12 | × 3 = double + one more. × 6 = × 5 + one more. × 12 = × 10 + × 2. |
| 9 | × 9 = × 10 take away one lot. The digits of the answer add to 9. Finger trick. |
| 7 and 11 | × 7 = × 5 + × 2 (learn 56 = 7 × 8). × 11: write the digit twice up to 9, then × 10 + one more. |
| Square numbers | 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144. |
| Division facts | Use the inverse: 56 ÷ 7 = ? means 7 × ? = 56. A fact family has 4 facts (2 if the factors are equal). |
| Special division | n ÷ 1 = n. n ÷ n = 1. 0 ÷ n = 0. Never divide by 0. |
| Factor pairs | Test 1, 2, 3, ... Write every pair that multiplies to make the number. 1 and the number itself are always a pair. |
| Three numbers | Multiply in any order. Look for a pair that makes 10 (like 2 × 5). |
| Known facts | 6 × 7 = 42 gives 60 × 7 = 420, 6 × 70 = 420 and 420 ÷ 7 = 60. Add or take away one group; double or halve. |
| Word problems | Draw a bar model. Total to find: multiply. Total to share or split: divide. Write the unit. |
Can you…?
- I can use arrays, equal groups and number lines to show multiplication.
- I know that 3 × 4 = 4 × 3, and I can multiply by 0 and 1 and divide by 1.
- I can recall every multiplication fact up to 12 × 12 and use a trick if I forget.
- I can recall the division facts that go with them.
- I can write a fact family and find missing numbers.
- I can find factor pairs of a number.
- I can multiply three numbers by choosing an easy pair first.
- I can use a known fact to work out facts like 60 × 7 and 420 ÷ 7.
- I can solve multiplication and division word problems with a bar model.
- I can answer times table questions quickly, in 6 seconds each.
Key terms
- Multiply
- To find the total of equal groups. 3 × 4 means 3 groups of 4.
- Product
- The answer to a multiplication.
- Factor
- A number that divides exactly into another number. Also, the numbers you multiply are called factors.
- Factor pair
- Two factors that multiply to make a number, such as 3 and 4 for 12.
- Multiple
- A number in a times table. The multiples of 4 are 4, 8, 12, 16...
- Array
- Objects in rows and columns.
- Commutative
- You can swap the order and the answer stays the same. 3 × 4 = 4 × 3.
- Square number
- A number multiplied by itself, such as 5 × 5 = 25.
- Double / Halve
- Double means × 2. Halve means ÷ 2.
- Inverse
- The opposite operation. Multiplying and dividing undo each other.
- Fact family
- The multiplication and division facts that use the same three numbers.
- Divide
- To share equally or to split into equal groups.
- Known fact
- A fact you can recall without working it out.
- Derived fact
- A new fact worked out from a known fact.
- Bar model
- A drawing of bars that shows the numbers in a problem.
Exercise 3Z Check-up (non-calculator)
Non-calculatorMethod. Eight is double double double. Double the number three times.
- Double once. This gives 2 lots.7 + 7 = 14
- Double again. This gives 4 lots.double 10 = 20, double 4 = 8, so 20 + 8 = 28
- Double a third time. This gives 8 lots.double 20 = 40, double 8 = 16, so 40 + 16 = 56
- Write the answer. 8 × 7 = 56
Check. Check by dividing: 56 ÷ 7 = 8. ✓
Watch out. Count your doubles. Three doubles give 8 lots. Two doubles only give 4.
Method. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 12 = 120
- Take away one group. 9 = 10 − 1, so take away the number itself once.120 − 12 = 108
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 12 = 108
Check. Check by dividing: 108 ÷ 9 = 12. ✓
Watch out. Take away 12, the other number, not 9. For 9 × 12 you work out 10 × 12 − 12.
Method. Use the 9 times table. Count up in 9s until you reach 72.
- Turn the division into a missing multiplication. 72 ÷ 9 asks: what do we multiply 9 by to get 72?72 ÷ 9 = ? means ? × 9 = 72
- Count up in 9s until you reach 72. Each number you say is one more group of 9.9, 18, 27, 36, 45, 54, 63, 72
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 9 = 72
- Write the answer. 72 ÷ 9 = 8
Check. Multiply back: 8 × 9 = 72. ✓
Watch out. Know your 9 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. We need the number that, multiplied by 6, makes 54.? × 6 = 54
- Use the inverse (opposite) operation. Order does not matter in multiplication. Divide 54 by 6.54 ÷ 6 = 9
- Write the missing number. 9 × 6 = 54
Check. Put it back: 9 × 6 = 54. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A fact family is a group of multiplication and division facts that use the same three numbers.
Method. A fact family uses three numbers. Two multiplication facts and two division facts use the same three numbers.
- Put the numbers in a fact triangle. The product goes at the top and the two factors at the bottom.
- Write the two multiplication facts. Multiply the bottom numbers in either order.4 × 9 = 36
9 × 4 = 36 - Write the two division facts. Start at the top and divide by one factor to get the other.36 ÷ 4 = 9
36 ÷ 9 = 4
Check. Check one fact: 4 × 9 = 36, so 36 ÷ 9 = 4. ✓
Watch out. In a division fact, the biggest number (the product) always comes first.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 7 × 6 = 42, and place value. 70 is 7 tens, so the answer is 42 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.7 × 6 = 42
- Say the bigger number in tens. 70 is 7 tens.70 = 7 tens
- Multiply, using the known fact. 7 tens × 6 = 42 tens, because 7 × 6 = 42.7 × 6 = 42, so 7 tens × 6 = 42 tens
- Change 42 tens back to a number. 1 ten is 10, so 42 tens is 42 × 10. 42 tens = 420
- Write the answer. 70 × 6 = 420
Check. Divide back: 420 ÷ 6 = 70. ✓
Watch out. The answer is 42 tens, which has 1 zero on the end. Count the zeros carefully.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 18. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 18 = 18 (a pair: 1 and 18)
2 × 9 = 18 (a pair: 2 and 9)
3 × 6 = 18 (a pair: 3 and 6)
4 × 4 = 16 and 4 × 5 = 20: 18 is in between, so 4 is not a factor - Stop when the numbers meet. After 4, the next factors would just be pairs we have already found the other way round.We can stop at 4.
- Write the factor pairs. 1 × 18 = 18
2 × 9 = 18
3 × 6 = 18 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 3, 6, 9, 18
Check. There are 6 factors: 1, 2, 3, 6, 9, 18. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 2 × 5 = 10, and multiplying by 10 is easy.2 × 5 = 10
- Multiply the answer by the last number, 6. 10 × 6 is a times table fact.6 tens
6 → 60
10 × 6 = 60 - Write the answer. 2 × 5 × 6 = 60
Check. Try a different order: 5 × 6 = 30, then 30 × 2 = 60. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Method. There are 9 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 9 equal bars show 9 equal boxes. Each bar is 6. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.9 × 6
- Work it out. Use a times table trick.10 × 6 = 60
60 − 6 = 54
9 × 6 = 54 - Write the answer. Include the unit.54 cupcakes
Check. Divide back: 54 ÷ 9 = 6. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Dividing is the opposite of multiplying. Use the times table to find how many times the number fits.
- Draw a bar model. The whole is 96. Each bar is 8. We want to know how many bars. (The picture shows only some of the bars.)
- Choose the operation. We want to know how many groups of 8 fit into 96. That is a division.96 ÷ 8
- Use the times tables. Think: what do we multiply 8 by to get 96?12 × 8 = 96, so 96 ÷ 8 = 12
- Write the answer. Include the unit.12 bags
Check. Multiply back: 12 × 8 = 96. ✓
Watch out. Read the question carefully. Does it ask for the size of each group, or for how many groups?
Total 17 marks. Allow about 17 minutes.
Exercise 3X SATs-style questions
Non-calculatorMethod. Nine is one less than ten. Multiply by 10, then take away one group.
- Multiply by 10. 10 lots of the number first.10 × 6 = 60
- Take away one group. 9 = 10 − 1, so take away the number itself once.60 − 6 = 54
- Write the answer. Answers in the 9 times table have digits that add up to 9 (or 18).9 × 6 = 54
Check. The digits of 54 add up to 9: 5 + 4 = 9. ✓
Watch out. Take away 6, the other number, not 9. For 9 × 6 you work out 10 × 6 − 6.
Method. Use the 12 times table. Count up in 12s until you reach 96.
- Turn the division into a missing multiplication. 96 ÷ 12 asks: what do we multiply 12 by to get 96?96 ÷ 12 = ? means ? × 12 = 96
- Count up in 12s until you reach 96. Each number you say is one more group of 12.12, 24, 36, 48, 60, 72, 84, 96
- Count how many numbers you said. The number of jumps is the answer.I said 8 numbers, so 8 × 12 = 96
- Write the answer. 96 ÷ 12 = 8
Check. Multiply back: 8 × 12 = 96. ✓
Watch out. Know your 12 times table facts, then division is quick.
Key words. A missing number is a number you have to find. Division and multiplication are inverses (opposites): they undo each other.
Method. Use the inverse operation. Multiplication and division undo each other.
- Say what the sentence means. A number divided by 7 gives 9.? ÷ 7 = 9
- Use the inverse (opposite) operation. The opposite of dividing by 7 is multiplying by 7.9 × 7 = 63
- Write the missing number. 63 ÷ 7 = 9
Check. Put it back: 63 ÷ 7 = 9. ✓
Watch out. Do not just put the numbers in the box in the order you see them. Think about what the sentence means.
Key words. A known fact is a multiplication fact you can already recall. A derived fact is a new fact you work out from a known fact.
Method. Use the fact you know, 6 × 8 = 48, and place value. 60 is 6 tens, so the answer is 48 tens.
- Spot the fact you know. Take away the zeros and look at the digits that are left.6 × 8 = 48
- Say the bigger number in tens. 60 is 6 tens.60 = 6 tens
- Multiply, using the known fact. 6 tens × 8 = 48 tens, because 6 × 8 = 48.6 × 8 = 48, so 6 tens × 8 = 48 tens
- Change 48 tens back to a number. 1 ten is 10, so 48 tens is 48 × 10. 48 tens = 480
- Write the answer. 60 × 8 = 480
Check. Divide back: 480 ÷ 8 = 60. ✓
Watch out. The answer is 48 tens, which has 1 zero on the end. Count the zeros carefully.
Method. There are 9 equal groups, so multiply the number in one group by the number of groups.
- Draw a bar model. 9 equal bars show 9 equal packs. Each bar is 12. We want the total.
- Choose the operation. Equal groups: multiply the number of groups by the amount in each group.9 × 12
- Work it out. Use a times table trick.10 × 12 = 120
120 − 12 = 108
9 × 12 = 108 - Write the answer. Include the unit.108 pencils
Check. Divide back: 108 ÷ 9 = 12. ✓
Watch out. Check that you multiplied. Equal groups mean the total is bigger than the size of one group.
Method. Work out 6 × 8 first. Then work out each choice and find the two that match.
- Work out 6 × 8. Use the 8 times table: double three times.8 × 6 = 48
- Work out each choice. A: 4 × 12 = 48
B: 7 × 7 = 49
C: 8 × 6 = 48
D: 9 × 5 = 45 - Choose the two that make 48. C is 8 × 6, the same numbers swapped. A is another pair of factors of 48.A and C
Check. 48 ÷ 4 = 12 and 48 ÷ 8 = 6. ✓
Watch out. 2 marks: 1 mark for each correct box. If you tick three boxes you lose the marks.
Key words. A factor of a number is a whole number that divides into it exactly. A factor pair is two factors that multiply to make the number.
Method. A factor pair is two numbers that multiply to make 28. Test 1, 2, 3, ... in order, and write down every pair you find.
- Start at 1 and try each number in turn. A factor pair is two numbers that multiply to make the number. We test 1, 2, 3, ... using the times tables.1 × 28 = 28 (a pair: 1 and 28)
2 × 14 = 28 (a pair: 2 and 14)
3 × 9 = 27 and 3 × 10 = 30: 28 is in between, so 3 is not a factor
4 × 7 = 28 (a pair: 4 and 7)
5 × 5 = 25 and 5 × 6 = 30: 28 is in between, so 5 is not a factor - Stop when the numbers meet. After 5, the next factors would just be pairs we have already found the other way round.We can stop at 5.
- Write the factor pairs. 1 × 28 = 28
2 × 14 = 28
4 × 7 = 28 - Picture them. Each pair makes a different array of the same number of squares.
- List all the factors in order. Each number in a pair is a factor.1, 2, 4, 7, 14, 28
Check. There are 6 factors: 1, 2, 4, 7, 14, 28. Every factor pairs up with another. ✓
Watch out. Do not forget 1 and the number itself. Every number has the pair 1 and itself.
Key words. You can multiply three numbers in any order and the answer is the same.
Method. Multiplication can be done in any order, so look for two numbers that are easy to multiply first.
- Choose two numbers to multiply first. 4 × 5 = 20, a multiple of 10, which is easy to multiply.4 × 5 = 20
- Multiply the answer by the last number, 7. 20 is 2 tens. Work out 2 × 7, then say that many tens.2 × 7 = 14, so 2 tens × 7 = 14 tens
14 tens = 140 - Write the answer. 4 × 5 × 7 = 140
Check. Try a different order: 5 × 7 = 35, then 35 × 4 = 140. ✓
Watch out. You can multiply in any order. Pick the pair that gives an easy answer, like a pair that makes 10.
Method. Check Leo’s answer with the digit test for the 9 times table, then work out the right answer.
- Add the digits of Leo’s answer. Every answer in the 9 times table has digits that add to 9.6 + 2 = 8
- Compare with 9. 8 is not 9, so 62 is not in the 9 times table.Leo is wrong.
- Work out 9 × 7. Ten lots take away one lot.10 × 7 = 70, then 70 − 7 = 63
- Check the new answer. 6 + 3 = 9. ✓ 9 × 7 = 63
Check. 63 ÷ 9 = 7. ✓
Watch out. 2 marks: 1 mark for showing Leo is wrong (the digits do not add to 9) and 1 mark for the correct answer, 63.
Method. Work out how many pens and how many pencils, then add the two totals.
- Pens. 7 packs of 8 pens.7 + 7 = 14
double 10 = 20, double 4 = 8, so 20 + 8 = 28
double 20 = 40, double 8 = 16, so 40 + 16 = 56
7 × 8 = 56 - Pencils. 9 packs of 6 pencils.10 × 6 = 60
60 − 6 = 54
9 × 6 = 54 - Add the two totals. 56 + 54 = 110
Check. 110 − 56 = 54 and 54 ÷ 6 = 9. ✓
Watch out. 3 marks: 1 for 7 × 8, 1 for 9 × 6, and 1 for adding to get 110.