Year 4: Multiplying and dividing by 10 and 100
Part of the Year 4 short multiplication and short division chapter. Chapter overview · whole chapter on one page · Download worksheet (PDF) · Answers (PDF)
Multiplying and dividing by 10 and 100
Each column in a number is worth ten times the column on its right. Ones, tens, hundreds, thousands: every step to the left makes the value ten times bigger. That is why multiplying and dividing by 10 and 100 is so quick. You only have to move the digits.
Multiplying by 10. Take 34. It is 3 tens and 4 ones. Multiply by 10 and every digit becomes ten times bigger. 3 tens become 3 hundreds. 4 ones become 4 tens. Every digit moves one place to the left. That leaves the ones place empty, so we fill it with a 0. So 34 × 10 = 340.
Multiplying by 100 makes every digit 100 times bigger. Every digit moves two places to the left and two zeros fill the gaps. 52 × 100 = 5,200. It is the same as multiplying by 10 and then by 10 again.
Dividing is the opposite. Dividing by 10 makes every digit ten times smaller, so each digit moves one place to the right. Dividing by 100 moves each digit two places to the right. In this chapter the numbers divide exactly, which means they end in enough zeros. 4,500 ÷ 100 = 45.
The zero is a place holder. You may have heard “just add a zero”. That is not the real rule. The digits move, and the zero only holds the empty place so that the other digits stay in the right columns. This matters: 305 × 10 = 3,050, and when you divide, only the zeros at the end fall off: 3,050 ÷ 10 = 305.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value is what each digit is worth.
Key ideas
- × 10: every digit moves 1 place to the left. Put a 0 in the ones place.
- × 100: every digit moves 2 places to the left. Put 0 in the tens and ones places.
- ÷ 10: every digit moves 1 place to the right. (The number must end in 0.)
- ÷ 100: every digit moves 2 places to the right. (The number must end in 00.)
- × 100 is the same as × 10 and then × 10 again.
- Multiplying and dividing undo each other: 34 × 10 = 340 and 340 ÷ 10 = 34.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.3 tens
6 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.3 tens become 3 hundreds
6 ones become 6 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
- Write the answer. The zero place holders keep every digit in the right column.36 × 10 = 360
Check. Divide back: 360 ÷ 10 = 36. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.4 tens
7 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.4 tens become 4 thousands
7 ones become 7 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
- Write the answer. The zero place holders keep every digit in the right column.47 × 100 = 4,700
Check. Divide back: 4,700 ÷ 100 = 47. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.520 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.5 hundreds become 5 tens
2 tens become 2 ones - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 520 5 2 0 ÷ 10 → 1 place right 52 5 2 - Write the answer. 520 ÷ 10 = 52
Check. Multiply back: 52 × 10 = 520. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.3,400 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.3 thousands become 3 tens
4 hundreds become 4 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 3,400 3 4 0 0 ÷ 100 → 2 places right 34 3 4 - Write the answer. 3,400 ÷ 100 = 34
Check. Multiply back: 34 × 100 = 3,400. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.3 hundreds
5 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.3 hundreds become 3 thousands
5 ones become 5 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 305 3 0 5 × 10 ← 1 place left 3,050 3 0 5 0 - Write the answer. The zero place holders keep every digit in the right column.305 × 10 = 3,050
Check. Divide back: 3,050 ÷ 10 = 305. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Find out how far the digits move. One place to the left is × 10. Two places to the left is × 100.
- Compare the two numbers. 45 is on one side, 4,500 is the answer.45 → 4,500
- Count how many places the digits moved. Each digit of 45 moved to the left. Count the places.
Th H T O 45 4 5 × 100 ← 2 places left 4,500 4 5 0 0 - Say what the number is. Digits that move 2 places to the left mean × 100.45 × 100 = 4,500
Check. 45 × 100 = 4,500. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Choose the operation. Each packet holds 100 stickers, so we multiply the number of packets by 100.28 × 100
- Say what each digit is worth. The digits have different values because of their columns.2 tens
8 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.2 tens become 2 thousands
8 ones become 8 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 28 2 8 × 100 ← 2 places left 2,800 2 8 0 0 - Write the answer. Include the unit.2,800 stickers
Check. Divide back: 2,800 ÷ 100 = 28. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Watch out
Do not just “add a zero” or “take away a zero”. Think about the digits moving. To multiply by 100, move two places (two zeros). To divide by 10, take off one zero only: 600 ÷ 10 = 60, not 6. And a zero inside a number stays: 305 × 10 = 3,050.Exercise 4A Multiplying and dividing by 10 and 100
Non-calculatorKey words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.8 ones
- Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.8 ones become 8 tens
- Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 8 8 × 10 ← 1 place left 80 8 0 - Write the answer. The zero place holders keep every digit in the right column.8 × 10 = 80
Check. Divide back: 80 ÷ 10 = 8. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.2 tens
3 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.2 tens become 2 hundreds
3 ones become 3 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 23 2 3 × 10 ← 1 place left 230 2 3 0 - Write the answer. The zero place holders keep every digit in the right column.23 × 10 = 230
Check. Divide back: 230 ÷ 10 = 23. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.6 tens
5 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.6 tens become 6 hundreds
5 ones become 5 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 65 6 5 × 10 ← 1 place left 650 6 5 0 - Write the answer. The zero place holders keep every digit in the right column.65 × 10 = 650
Check. Divide back: 650 ÷ 10 = 65. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.9 tens
- Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.9 tens become 9 hundreds
- Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 90 9 0 × 10 ← 1 place left 900 9 0 0 - Write the answer. The zero place holders keep every digit in the right column.90 × 10 = 900
Check. Divide back: 900 ÷ 10 = 90. ✓
Watch out. The zeros are place holders. Count them: 90 × 10 must end with 1 zero more than the zeros 90 already ends with.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.1 hundred
4 tens
7 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.1 hundred becomes 1 thousand
4 tens become 4 hundreds
7 ones become 7 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 147 1 4 7 × 10 ← 1 place left 1,470 1 4 7 0 - Write the answer. The zero place holders keep every digit in the right column.147 × 10 = 1,470
Check. Divide back: 1,470 ÷ 10 = 147. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.3 hundreds
8 tens - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.3 hundreds become 3 thousands
8 tens become 8 hundreds - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 380 3 8 0 × 10 ← 1 place left 3,800 3 8 0 0 - Write the answer. The zero place holders keep every digit in the right column.380 × 10 = 3,800
Check. Divide back: 3,800 ÷ 10 = 380. ✓
Watch out. The zeros are place holders. Count them: 380 × 10 must end with 1 zero more than the zeros 380 already ends with.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.4 ones
- Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.4 ones become 4 hundreds
- Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 4 4 × 100 ← 2 places left 400 4 0 0 - Write the answer. The zero place holders keep every digit in the right column.4 × 100 = 400
Check. Divide back: 400 ÷ 100 = 4. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.1 ten
7 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.1 ten becomes 1 thousand
7 ones become 7 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 17 1 7 × 100 ← 2 places left 1,700 1 7 0 0 - Write the answer. The zero place holders keep every digit in the right column.17 × 100 = 1,700
Check. Divide back: 1,700 ÷ 100 = 17. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.6 tens
- Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.6 tens become 6 thousands
- Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 60 6 0 × 100 ← 2 places left 6,000 6 0 0 0 - Write the answer. The zero place holders keep every digit in the right column.60 × 100 = 6,000
Check. Divide back: 6,000 ÷ 100 = 60. ✓
Watch out. The zeros are place holders. Count them: 60 × 100 must end with 2 zeros more than the zeros 60 already ends with.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.2 hundreds
5 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.2 hundreds become 2 ten thousands
5 ones become 5 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
TTh Th H T O 205 2 0 5 × 100 ← 2 places left 20,500 2 0 5 0 0 - Write the answer. The zero place holders keep every digit in the right column.205 × 100 = 20,500
Check. Divide back: 20,500 ÷ 100 = 205. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.3 hundreds
8 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.3 hundreds become 3 ten thousands
8 ones become 8 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
TTh Th H T O 308 3 0 8 × 100 ← 2 places left 30,800 3 0 8 0 0 - Write the answer. The zero place holders keep every digit in the right column.308 × 100 = 30,800
Check. Divide back: 30,800 ÷ 100 = 308. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.9 tens
9 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.9 tens become 9 thousands
9 ones become 9 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 99 9 9 × 100 ← 2 places left 9,900 9 9 0 0 - Write the answer. The zero place holders keep every digit in the right column.99 × 100 = 9,900
Check. Divide back: 9,900 ÷ 100 = 99. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.70 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.7 tens become 7 ones
- Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 70 7 0 ÷ 10 → 1 place right 7 7 - Write the answer. 70 ÷ 10 = 7
Check. Multiply back: 7 × 10 = 70. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.340 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.3 hundreds become 3 tens
4 tens become 4 ones - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 340 3 4 0 ÷ 10 → 1 place right 34 3 4 - Write the answer. 340 ÷ 10 = 34
Check. Multiply back: 34 × 10 = 340. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.800 ends in 2 zeros. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.8 hundreds become 8 tens
- Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 800 8 0 0 ÷ 10 → 1 place right 80 8 0 - Write the answer. 800 ÷ 10 = 80
Check. Multiply back: 80 × 10 = 800. ✓
Watch out. Take away 1 zero from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.1,250 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.1 thousand becomes 1 hundred
2 hundreds become 2 tens
5 tens become 5 ones - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 1,250 1 2 5 0 ÷ 10 → 1 place right 125 1 2 5 - Write the answer. 1,250 ÷ 10 = 125
Check. Multiply back: 125 × 10 = 1,250. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.4,060 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.4 thousands become 4 hundreds
6 tens become 6 ones - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 4,060 4 0 6 0 ÷ 10 → 1 place right 406 4 0 6 - Write the answer. 4,060 ÷ 10 = 406
Check. Multiply back: 406 × 10 = 4,060. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.9,000 ends in 3 zeros. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.9 thousands become 9 hundreds
- Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 9,000 9 0 0 0 ÷ 10 → 1 place right 900 9 0 0 - Write the answer. 9,000 ÷ 10 = 900
Check. Multiply back: 900 × 10 = 9,000. ✓
Watch out. Take away 1 zero from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.600 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.6 hundreds become 6 ones
- Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 600 6 0 0 ÷ 100 → 2 places right 6 6 - Write the answer. 600 ÷ 100 = 6
Check. Multiply back: 6 × 100 = 600. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.4,700 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.4 thousands become 4 tens
7 hundreds become 7 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 4,700 4 7 0 0 ÷ 100 → 2 places right 47 4 7 - Write the answer. 4,700 ÷ 100 = 47
Check. Multiply back: 47 × 100 = 4,700. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.3,000 ends in 3 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.3 thousands become 3 tens
- Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 3,000 3 0 0 0 ÷ 100 → 2 places right 30 3 0 - Write the answer. 3,000 ÷ 100 = 30
Check. Multiply back: 30 × 100 = 3,000. ✓
Watch out. Take away 2 zeros from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.9,500 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.9 thousands become 9 tens
5 hundreds become 5 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 9,500 9 5 0 0 ÷ 100 → 2 places right 95 9 5 - Write the answer. 9,500 ÷ 100 = 95
Check. Multiply back: 95 × 100 = 9,500. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.7,200 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.7 thousands become 7 tens
2 hundreds become 2 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 7,200 7 2 0 0 ÷ 100 → 2 places right 72 7 2 - Write the answer. 7,200 ÷ 100 = 72
Check. Multiply back: 72 × 100 = 7,200. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.8,000 ends in 3 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.8 thousands become 8 tens
- Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 8,000 8 0 0 0 ÷ 100 → 2 places right 80 8 0 - Write the answer. 8,000 ÷ 100 = 80
Check. Multiply back: 80 × 100 = 8,000. ✓
Watch out. Take away 2 zeros from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.5 tens
6 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.5 tens become 5 hundreds
6 ones become 6 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 56 5 6 × 10 ← 1 place left 560 5 6 0 - Write the answer. The zero place holders keep every digit in the right column.56 × 10 = 560
Check. Divide back: 560 ÷ 10 = 56. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.300 ends in 2 zeros. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.3 hundreds become 3 tens
- Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 300 3 0 0 ÷ 10 → 1 place right 30 3 0 - Write the answer. 300 ÷ 10 = 30
Check. Multiply back: 30 × 10 = 300. ✓
Watch out. Take away 1 zero from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.7 ones
- Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.7 ones become 7 hundreds
- Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 7 7 × 100 ← 2 places left 700 7 0 0 - Write the answer. The zero place holders keep every digit in the right column.7 × 100 = 700
Check. Divide back: 700 ÷ 100 = 7. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.2,900 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.2 thousands become 2 tens
9 hundreds become 9 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 2,900 2 9 0 0 ÷ 100 → 2 places right 29 2 9 - Write the answer. 2,900 ÷ 100 = 29
Check. Multiply back: 29 × 100 = 2,900. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.4 hundreds
1 ten - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.4 hundreds become 4 thousands
1 ten becomes 1 hundred - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 410 4 1 0 × 10 ← 1 place left 4,100 4 1 0 0 - Write the answer. The zero place holders keep every digit in the right column.410 × 10 = 4,100
Check. Divide back: 4,100 ÷ 10 = 410. ✓
Watch out. The zeros are place holders. Count them: 410 × 10 must end with 1 zero more than the zeros 410 already ends with.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.6,000 ends in 3 zeros. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.6 thousands become 6 hundreds
- Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 6,000 6 0 0 0 ÷ 10 → 1 place right 600 6 0 0 - Write the answer. 6,000 ÷ 10 = 600
Check. Multiply back: 600 × 10 = 6,000. ✓
Watch out. Take away 1 zero from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.8 tens
3 ones - Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.8 tens become 8 thousands
3 ones become 3 hundreds - Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 83 8 3 × 100 ← 2 places left 8,300 8 3 0 0 - Write the answer. The zero place holders keep every digit in the right column.83 × 100 = 8,300
Check. Divide back: 8,300 ÷ 100 = 83. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.500 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.5 hundreds become 5 ones
- Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 500 5 0 0 ÷ 100 → 2 places right 5 5 - Write the answer. 500 ÷ 100 = 5
Check. Multiply back: 5 × 100 = 500. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Method. Look at where the digits start and where they finish. The direction and the number of places tell you whether it is multiply or divide, and by what.
- Read the top number and the bottom number. The top row is the starting number. The bottom row is the answer.Top: 38. Bottom: 380.
- Look at the arrows. The digits move 1 place to the left. Moving to the left makes numbers bigger.1 place to the left means × 10.
- Write the calculation. 38 × 10 = 380
Check. Divide back: 380 ÷ 10 = 38. ✓
Watch out. Digits moving to the left means multiply. Digits moving to the right means divide.
Method. Look at where the digits start and where they finish. The direction and the number of places tell you whether it is multiply or divide, and by what.
- Read the top number and the bottom number. The top row is the starting number. The bottom row is the answer.Top: 6,700. Bottom: 67.
- Look at the arrows. The digits move 2 places to the right. Moving to the right makes numbers smaller.2 places to the right means ÷ 100.
- Write the calculation. 6,700 ÷ 100 = 67
Check. Multiply back: 67 × 100 = 6,700. ✓
Watch out. Digits moving to the left means multiply. Digits moving to the right means divide.
Method. Look at where the digits start and where they finish. The direction and the number of places tell you whether it is multiply or divide, and by what.
- Read the top number and the bottom number. The top row is the starting number. The bottom row is the answer.Top: 52. Bottom: 5,200.
- Look at the arrows. The digits move 2 places to the left. Moving to the left makes numbers bigger.2 places to the left means × 100.
- Write the calculation. 52 × 100 = 5,200
Check. Divide back: 5,200 ÷ 100 = 52. ✓
Watch out. Digits moving to the left means multiply. Digits moving to the right means divide.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Find out how far the digits move. One place to the left is × 10. Two places to the left is × 100.
- Compare the two numbers. 45 is on one side, 4,500 is the answer.45 → 4,500
- Count how many places the digits moved. Each digit of 45 moved to the left. Count the places.
Th H T O 45 4 5 × 100 ← 2 places left 4,500 4 5 0 0 - Say what the number is. Digits that move 2 places to the left mean × 100.45 × 100 = 4,500
Check. 45 × 100 = 4,500. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Find out how far the digits move. One place to the left is × 10. Two places to the left is × 100.
- Compare the two numbers. 8 is on one side, 80 is the answer.8 → 80
- Count how many places the digits moved. Each digit of 8 moved to the left. Count the places.
Th H T O 8 8 × 10 ← 1 place left 80 8 0 - Say what the number is. Digits that move 1 place to the left mean × 10.8 × 10 = 80
Check. 8 × 10 = 80. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Multiplying and dividing undo each other. Divide the answer by 10 to find the missing number.
- Use the opposite (inverse) operation. ? × 10 = 370, so 370 ÷ 10 gives the missing number.370 ÷ 10
- Move the digits 1 place to the right. Dividing by 10 makes each digit 10 times smaller.
Th H T O 370 3 7 0 ÷ 10 → 1 place right 37 3 7 - Write the missing number. 37 × 10 = 370
Check. 37 × 10 = 370. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Multiplying and dividing undo each other. Divide the answer by 100 to find the missing number.
- Use the opposite (inverse) operation. ? × 100 = 6,200, so 6,200 ÷ 100 gives the missing number.6,200 ÷ 100
- Move the digits 2 places to the right. Dividing by 100 makes each digit 100 times smaller.
Th H T O 6,200 6 2 0 0 ÷ 100 → 2 places right 62 6 2 - Write the missing number. 62 × 100 = 6,200
Check. 62 × 100 = 6,200. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Multiplying and dividing undo each other. Multiply 54 by 10 to find the missing number.
- Use the opposite (inverse) operation. The missing number is 10 times bigger than 54.54 × 10
- Move the digits 1 place to the left. Multiplying by 10 makes each digit 10 times bigger.
Th H T O 54 5 4 × 10 ← 1 place left 540 5 4 0 - Write the missing number. 540 ÷ 10 = 54
Check. 540 ÷ 10 = 54. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Find out how far the digits move. One place to the right is ÷ 10. Two places to the right is ÷ 100.
- Compare the two numbers. 900 is divided by the missing number to make 9.900 → 9
- Count how many places the digits moved. Each digit of 900 moved to the right.
Th H T O 900 9 0 0 ÷ 100 → 2 places right 9 9 - Say what the number is. Digits that move 2 places to the right mean ÷ 100.900 ÷ 100 = 9
Check. 9 × 100 = 900. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.7 tens
6 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.7 tens become 7 hundreds
6 ones become 6 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 76 7 6 × 10 ← 1 place left 760 7 6 0 - Write the answer. The zero place holders keep every digit in the right column.76 × 10 = 760
Check. Divide back: 760 ÷ 10 = 76. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 100, move every digit 2 places to the left and put 2 zeros in the empty places on the right. Do not just “add a zero”: it is the digits that move.
- Say what each digit is worth. The digits have different values because of their columns.9 ones
- Make every digit 100 times bigger. Multiplying by 100 makes each digit 100 times bigger. That moves it 2 places to the left.9 ones become 9 hundreds
- Show it in a place-value table. The 2 gaps on the right are empty, so we put zeros there.
Th H T O 9 9 × 100 ← 2 places left 900 9 0 0 - Write the answer. The zero place holders keep every digit in the right column.9 × 100 = 900
Check. Divide back: 900 ÷ 100 = 9. ✓
Watch out. Move the digits, then fill the empty places with zeros. Check the answer is 100 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.830 ends in 1 zero. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.8 hundreds become 8 tens
3 tens become 3 ones - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 830 8 3 0 ÷ 10 → 1 place right 83 8 3 - Write the answer. 830 ÷ 10 = 83
Check. Multiply back: 83 × 10 = 830. ✓
Watch out. Move the digits 1 place to the right. Check the answer is 10 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.6,100 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.6 thousands become 6 tens
1 hundred becomes 1 one - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 6,100 6 1 0 0 ÷ 100 → 2 places right 61 6 1 - Write the answer. 6,100 ÷ 100 = 61
Check. Multiply back: 61 × 100 = 6,100. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Choose the operation. There are 10 pencils in each box, so we multiply the number of boxes by 10.85 × 10
- Say what each digit is worth. The digits have different values because of their columns.8 tens
5 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.8 tens become 8 hundreds
5 ones become 5 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 85 8 5 × 10 ← 1 place left 850 8 5 0 - Write the answer. Include the unit.850 pencils
Check. Divide back: 850 ÷ 10 = 85. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To multiply by 10, move every digit 1 place to the left and put a zero in the empty place on the right. Do not just “add a zero”: it is the digits that move.
- Choose the operation. Each sweet costs 10p, so we multiply the number of sweets by 10.64p × 10
- Say what each digit is worth. The digits have different values because of their columns.6 tens
4 ones - Make every digit 10 times bigger. Multiplying by 10 makes each digit 10 times bigger. That moves it 1 place to the left.6 tens become 6 hundreds
4 ones become 4 tens - Show it in a place-value table. The 1 gap on the right is empty, so we put a zero there.
Th H T O 64 6 4 × 10 ← 1 place left 640 6 4 0 - Write the answer. Include the unit.640p
Check. Divide back: 640 ÷ 10 = 64. ✓
Watch out. Move the digits, then fill the empty place with a zero. Check the answer is 10 times bigger.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 100, move every digit 2 places to the right. A number that ends in 2 zeros will divide exactly.
- Choose the operation. 100 cm make 1 m, so we divide the number of centimetres by 100.3,500 ÷ 100
- Look at the end of the number. Are there at least 2 zeros? Every digit moves 2 places to the right, so the ones column must be able to hold the moved digits. A number that ends in 2 zeros divides exactly.3,500 ends in 2 zeros. ✓
- Make every digit 100 times smaller. Dividing by 100 makes each digit 100 times smaller. That moves it 2 places to the right.3 thousands become 3 tens
5 hundreds become 5 ones - Show it in a place-value table. The last 2 zeros fall off the end.
Th H T O 3,500 3 5 0 0 ÷ 100 → 2 places right 35 3 5 - Write the answer. Include the unit.35 m
Check. Multiply back: 35 × 100 = 3,500. ✓
Watch out. Move the digits 2 places to the right. Check the answer is 100 times smaller.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Zainab said she “took away both zeros”. Check by moving the digits.
- Move the digits for ÷ 10. Dividing by 10 moves every digit one place to the right.
Th H T O 700 7 0 0 ÷ 10 → 1 place right 70 7 0 - Read the answer. 700 ÷ 10 = 70. Zainab took off two zeros, which is dividing by 100.700 ÷ 10 = 70, and 700 ÷ 100 = 7
- Answer Zainab. No. The answer is 70.
Check. Multiply back: 70 × 10 = 700. ✓
Watch out. Dividing by 10 takes off ONE zero. Dividing by 100 takes off two.
Method. Think about where the digits go when you multiply a whole number by 10.
- Try some numbers. Multiply by 10 and look at the last digit.7 × 10 = 70 45 × 10 = 450 300 × 10 = 3,000 1,234 × 10 = 12,340
- Explain why. Every digit moves one place to the left, so the ones place is empty. We always put a 0 there.
Th H T O 45 4 5 × 10 ← 1 place left 450 4 5 0 - Decide. Always
Check. Divide back: 450 ÷ 10 = 45. ✓
Watch out. “Always” means it works every time. Give a reason, not just examples.
Method. Work out each one. The odd one out has a different answer from the others.
- Work out A and B. Move the digits.5 × 100 = 500 and 50 × 10 = 500
- Work out C. 500 has two zeros, and one more zero goes on.500 × 10 = 5,000
- Work out D. Dividing by 10 takes one zero off.5,000 ÷ 10 = 500
- Choose the odd one out. A, B and D all make 500. C makes 5,000.C (500 × 10)
Check. 5,000 ÷ 10 = 500, so D is 500 and C is ten times bigger. ✓
Watch out. Check the sign (× or ÷) as well as the numbers.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. Multiplying and dividing undo each other. Divide the answer by 100 to find the missing number.
- Use the opposite (inverse) operation. ? × 100 = 6,300, so 6,300 ÷ 100 gives the missing number.6,300 ÷ 100
- Move the digits 2 places to the right. Dividing by 100 makes each digit 100 times smaller.
Th H T O 6,300 6 3 0 0 ÷ 100 → 2 places right 63 6 3 - Write the missing number. 63 × 100 = 6,300
Check. 63 × 100 = 6,300. ✓
Watch out. Put your answer back in the box and read the whole sentence. It must be true.
Key words. A digit is one of the symbols 0 to 9. A place holder is a zero that keeps the other digits in the right columns. Place value tells you what each digit is worth.
Method. To divide by 10, move every digit 1 place to the right. A number that ends in 1 zero will divide exactly.
- Look at the end of the number. Are there at least 1 zero? Every digit moves 1 place to the right, so the ones column must be able to hold the moved digits. A number that ends in 1 zero divides exactly.6,300 ends in 2 zeros. ✓
- Make every digit 10 times smaller. Dividing by 10 makes each digit 10 times smaller. That moves it 1 place to the right.6 thousands become 6 hundreds
3 hundreds become 3 tens - Show it in a place-value table. The last 1 zero falls off the end.
Th H T O 6,300 6 3 0 0 ÷ 10 → 1 place right 630 6 3 0 - Write the answer. 6,300 ÷ 10 = 630
Check. Multiply back: 630 × 10 = 6,300. ✓
Watch out. Take away 1 zero from the end. Do not take away every zero: 600 ÷ 10 is 60, not 6.