Numbers to 20

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   11 − 10 = 1 one
3. Write the answer. Say it as a ten and some ones.
   11 is one ten and 1 one

Check. Ten and 1 more makes 11: 10 + 1 = 11. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   14 − 10 = 4 ones
3. Write the answer. Say it as a ten and some ones.
   14 is one ten and 4 ones

Check. Ten and 4 more makes 14: 10 + 4 = 14. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   17 − 10 = 7 ones
3. Write the answer. Say it as a ten and some ones.
   17 is one ten and 7 ones

Check. Ten and 7 more makes 17: 10 + 7 = 17. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   19 − 10 = 9 ones
3. Write the answer. Say it as a ten and some ones.
   19 is one ten and 9 ones

Check. Ten and 9 more makes 19: 10 + 9 = 19. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Method. Two full ten frames make twenty.

1. Look at the first frame. It is full, so it has ten.
   10
2. Look at the second frame. It is full too, so it has ten more.
   10 + 10
3. Write the answer.
   20

Check. Count in tens: 10, 20. ✓

Watch out. Two full frames is two tens, which is twenty.

Method. Use the ten and the ones to make the number.

1. Start with the ten. One ten is 10.
   10
2. Add the ones. Three ones are 3.
   10 + 3
3. Write the answer.
   13

Check. Count on from 10: 11, 12, 13. ✓

Watch out. Count on from 10, not from 1.

Method. Use the ten and the ones to make the number.

1. Start with the ten. One ten is 10.
   10
2. Add the ones. Eight ones are 8.
   10 + 8
3. Write the answer.
   18

Check. Count on from 10: 11, 12, 13, 14, 15, 16, 17, 18. ✓

Watch out. Eight ones makes 18 when they are added to 10.

Method. Ten and some more makes 15. Count on from 10 to find the missing ones.

1. Start at 10. That is the ten.
   10
2. Count on to 15. Count on one at a time: 11, 12, 13, 14, 15.
   11, 12, 13, 14, 15
3. Count the ones you added. Five ones were added.
   5
4. Write the answer.
   5

Check. 10 + 5 = 15. ✓

Watch out. The gap is the number of ones, not the number 15.

Method. Ten is one full set. The extra cubes are the ones left over.

1. Count the first ten. Ten cubes make one ten.
   10
2. Take away the ten. What is left is the ones.
   16 − 10 = 6
3. Write the answer.
   6

Check. Ten and six more makes 16: 10 + 6 = 16. ✓

Watch out. Count the ten first, then count what is left.

Method. A teen number has one ten, not two.

1. Think about 12. It is more than ten but less than twenty.
   12
2. Break 12 into parts. One ten and the rest are ones.
   10 + 2
3. Write the answer.
   No. 12 is one ten and two ones.

Check. Ten and two more makes 12. ✓

Watch out. Two tens would make 20, not 12.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   19 − 10 = 9 ones
3. Write the answer. Say it as a ten and some ones.
   19 is one ten and 9 ones

Check. Ten and 9 more makes 19: 10 + 9 = 19. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Method. Look at the digit in the tens place and the digit in the ones place.

1. Look at 15. The 1 is the tens and the 5 is the ones.
   1 ten and 5 ones
2. Look at 51. The 5 is the tens and the 1 is the ones.
   5 tens and 1 one
3. Write the answer.
   Accept any answer: 15 has one ten and five ones; 51 has five tens and one one.

Check. Check: 1 ten and 5 ones is 15. 5 tens and 1 one is 51. ✓

Watch out. The place of each digit matters.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “twelve”
2. Find the word on the list. Each word matches one number.
   twelve = 12
3. Write the numeral. A numeral uses digits.
   12

Check. Count 12 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “sixteen”
2. Find the word on the list. Each word matches one number.
   sixteen = 16
3. Write the numeral. A numeral uses digits.
   16

Check. Count 16 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “fifteen”
2. Find the word on the list. Each word matches one number.
   fifteen = 15
3. Write the numeral. A numeral uses digits.
   15

Check. Count 15 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   13
2. Find its name. Every number has one name.
   13 = thirteen
3. Write the word. Write each letter in order.
   thirteen

Check. Read the word back. It has the same number of things as 13. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   19
2. Find its name. Every number has one name.
   19 = nineteen
3. Write the word. Write each letter in order.
   nineteen

Check. Read the word back. It has the same number of things as 19. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   20
2. Find its name. Every number has one name.
   20 = twenty
3. Write the word. Write each letter in order.
   twenty

Check. Read the word back. It has the same number of things as 20. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “fourteen”
2. Find the word on the list. Each word matches one number.
   fourteen = 14
3. Write the numeral. A numeral uses digits.
   14

Check. Count 14 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   17
2. Find its name. Every number has one name.
   17 = seventeen
3. Write the word. Write each letter in order.
   seventeen

Check. Read the word back. It has the same number of things as 17. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Look at each part of the word. The word for 15 is spelled with f-i-f-t-e-e-n.

1. Say the number. It is five and ten joined together.
   5 and 10
2. Spell the word carefully. It is fifteen. The f is followed by i, f, t.
   f - i - f - t - e - e - n
3. Write the word.
   fifteen

Check. Count 15 things, then say the word fifteen. ✓

Watch out. Look at the middle of the word: fi-f-teen.

Method. Write each word as a numeral, then compare.

1. Write thirteen as a numeral. Thirteen is one ten and three ones.
   13
2. Write thirty as a numeral. Thirty is three tens.
   30
3. Compare the numbers. They are different numbers.
   13 is not 30
4. Write the answer.
   No. Thirteen is 13, and thirty is 30.

Check. Count on from 13: 14, 15, ... thirty is much further on. ✓

Watch out. The -teen word is smaller than the -ty word.

Method. Find 19 on the number track. The number after it is the answer.

1. Find 19. Put your finger on it.
   19
2. Move one box to the right. Each box is one more or one less.
   19 + 1 = 20
3. Write the answer.
   20

Check. Check it: 20 − 1 = 19. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 12 on the number track. The number before it is the answer.

1. Find 12. Put your finger on it.
   12
2. Move one box to the left. Each box is one more or one less.
   12 − 1 = 11
3. Write the answer.
   11

Check. Check it: 11 + 1 = 12. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Start at 5 and count on to 9. Each number is one more than the one before.

1. Start at 5. Say the first number.
   5
2. Count on to 9. Say each number, one more each time.
   5, 6, 7, 8, 9
3. Write the numbers. Write them in order.
   5, 6, 7, 8, 9

Check. Count back from 9 to 5. You say the same numbers in reverse. ✓

Watch out. Do not skip a number. Check each one is one more than the last.

Method. Start at 15 and count back to 12. Each number is one less than the one before.

1. Start at 15. Start with the biggest number.
   15
2. Count back to 12. Each number is one less.
   15, 14, 13, 12
3. Write the numbers. Include the first and last numbers.
   15, 14, 13, 12

Check. Count on from 12 to 15 to check. ✓

Watch out. Count back one at a time. Do not jump over a number.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   11, ?, 13, ?, 15
2. Add one to the number before each gap. That gives the missing number.
   Gap 2: 11 + 1 = 12
   Gap 4: 13 + 1 = 14
3. Write the missing numbers.
   12, 14

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   16, 17, ?, 19
2. Add one to the number before each gap. That gives the missing number.
   Gap 3: 17 + 1 = 18
3. Write the missing numbers.
   18

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Start at 17 and count on to 20. Each number is one more than the one before.

1. Start at 17. Say the first number.
   17
2. Count on to 20. Say each number, one more each time.
   17, 18, 19, 20
3. Write the numbers. Write them in order.
   17, 18, 19, 20

Check. Count back from 20 to 17. You say the same numbers in reverse. ✓

Watch out. Do not skip a number. Check each one is one more than the last.

Method. Start at 20 and count back to 16. Each number is one less than the one before.

1. Start at 20. Start with the biggest number.
   20
2. Count back to 16. Each number is one less.
   20, 19, 18, 17, 16
3. Write the numbers. Include the first and last numbers.
   20, 19, 18, 17, 16

Check. Count on from 16 to 20 to check. ✓

Watch out. Count back one at a time. Do not jump over a number.

Method. Find 6 on the number track. The number after it is the answer.

1. Find 6. Put your finger on it.
   6
2. Move one box to the right. Each box is one more or one less.
   6 + 1 = 7
3. Write the answer.
   7

Check. Check it: 7 − 1 = 6. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 10 on the number track. The number before it is the answer.

1. Find 10. Put your finger on it.
   10
2. Move one box to the left. Each box is one more or one less.
   10 − 1 = 9
3. Write the answer.
   9

Check. Check it: 9 + 1 = 10. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Start at 12 on the track. Count on 4 boxes, one at a time.

1. Start at 12. Put your finger on 12.
   12
2. Count on 4 boxes. Say each number as you move one box.
   13, 14, 15, 16
3. Write the answer. The last number you said is the answer.
   16

Check. Count back 4 from 16: 15, 14, 13, 12. You are back at 12. ✓

Watch out. Count on from 12, not from 13.

Method. Start at 18 and count back to 13. Each number is one less than the one before.

1. Start at 18. Start with the biggest number.
   18
2. Count back to 13. Each number is one less.
   18, 17, 16, 15, 14, 13
3. Write the numbers. Include the first and last numbers.
   18, 17, 16, 15, 14, 13

Check. Count on from 13 to 18 to check. ✓

Watch out. Count back one at a time. Do not jump over a number.

Method. Start at 16 and count on to 20. Each number is one more than the one before.

1. Start at 16. Say the first number.
   16
2. Count on to 20. Say each number, one more each time.
   16, 17, 18, 19, 20
3. Write the numbers. Write them in order.
   16, 17, 18, 19, 20

Check. Count back from 20 to 16. You say the same numbers in reverse. ✓

Watch out. Do not skip a number. Check each one is one more than the last.

Method. Count back from 20 to 15, one number at a time. Then count how many numbers you said.

1. Count back from 20 to 15. Say each number as you go down.
   20, 19, 18, 17, 16, 15
2. Count the numbers you said. Touch each number once.
   1, 2, 3, 4, 5, 6
3. Write the answer.
   Yes. There are 6 numbers from 20 down to 15.

Check. Count 15 to 20: 15, 16, 17, 18, 19, 20. Six numbers. ✓

Watch out. Count both ends, 20 and 15.

Method. Find 16 on the number track. The number after it is the answer.

1. Find 16. Put your finger on it.
   16
2. Move one box to the right. Each box is one more or one less.
   16 + 1 = 17
3. Write the answer.
   17

Check. Check it: 17 − 1 = 16. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 11 on the number track. The number before it is the answer.

1. Find 11. Put your finger on it.
   11
2. Move one box to the left. Each box is one more or one less.
   11 − 1 = 10
3. Write the answer.
   10

Check. Check it: 10 + 1 = 11. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. The number between 8 and 10 is in the middle of them.

1. Find 8 and 10. Put your fingers on both numbers.
   8 ... 10
2. Count on one from 8. The middle number is one more than the first.
   8 + 1 = 9
3. Write the answer.
   9

Check. Count on from 9 to 10: 9 + 1 = 10. ✓

Watch out. The number between is not one of the two you started with.

Method. Find 9 on the number track. The number after it is the answer.

1. Find 9. Put your finger on it.
   9
2. Move one box to the right. Each box is one more or one less.
   9 + 1 = 10
3. Write the answer.
   10

Check. Check it: 10 − 1 = 9. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 20 on the number track. The number before it is the answer.

1. Find 20. Put your finger on it.
   20
2. Move one box to the left. Each box is one more or one less.
   20 − 1 = 19
3. Write the answer.
   19

Check. Check it: 19 + 1 = 20. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. The number between 14 and 16 is in the middle of them.

1. Find 14 and 16. Put your fingers on both numbers.
   14 ... 16
2. Count on one from 14. The middle number is one more than the first.
   14 + 1 = 15
3. Write the answer.
   15

Check. Count on from 15 to 16: 15 + 1 = 16. ✓

Watch out. The number between is not one of the two you started with.

Method. Smallest first. Look at how many tens each number has, then the ones.

1. Look at the tens of each number. More tens means a bigger number.
   14, 9, 17, 11
2. Put the smallest first. Then put the next smallest.
   9, 11, 14, 17
3. Write the numbers in order. Check you have not left one out.
   9, 11, 14, 17

Check. There are 4 numbers in the question and 4 in the answer. ✓

Watch out. Compare the tens first. Only look at the ones if the tens are the same.

Method. Smallest first. Look at how many tens each number has, then the ones.

1. Look at the tens of each number. More tens means a bigger number.
   18, 12, 15
2. Put the smallest first. Then put the next smallest.
   12, 15, 18
3. Write the numbers in order. Check you have not left one out.
   12, 15, 18

Check. There are 3 numbers in the question and 3 in the answer. ✓

Watch out. Compare the tens first. Only look at the ones if the tens are the same.

Method. Count on from 13 to see which number comes later.

1. Find 13 and 18. Put your finger on each number.
   13 and 18
2. Count on from 13. The bigger number comes later when we count.
   14, 15, 16, 17, 18
3. Write the answer.
   18

Check. 18 comes after 13, so 18 is bigger. ✓

Watch out. The bigger number comes later when we count.

Method. The number between 12 and 14 is in the middle of them.

1. Find 12 and 14. Put your fingers on both numbers.
   12 ... 14
2. Count on one from 12. The middle number is one more than the first.
   12 + 1 = 13
3. Write the answer.
   13

Check. Count on from 13 to 14: 13 + 1 = 14. ✓

Watch out. The number between is not one of the two you started with.

Method. Look at the numbers. Find the next one in the pattern.

1. Look at the numbers. Each number is one more than the one before.
   15, 16, 17
2. Find the next number. One more than 17 is 18.
   17 + 1 = 18
3. Write the answer.
   18

Check. Count 15, 16, 17, 18. ✓

Watch out. Each number is one more than the one before it.

Method. Count up from 13 and look at which number comes next.

1. Count from 13. Say the number after 13.
   13, 14
2. Check the order. If we count up, 13 comes first and 14 comes after.
   13 before 14
3. Write the answer.
   No. 13 comes before 14, so 14 comes after 13.

Check. Count 13, 14. Thirteen is first. ✓

Watch out. Count up to find which number comes first.

Method. Find 20 on the number track. The number after it is the answer.

1. Find 20. Put your finger on it.
   20
2. Move one box to the right. Each box is one more or one less.
   20 + 1 = 21
3. Write the answer.
   21

Check. Check it: 21 − 1 = 20. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 24 on the number track. The number after it is the answer.

1. Find 24. Put your finger on it.
   24
2. Move one box to the right. Each box is one more or one less.
   24 + 1 = 25
3. Write the answer.
   25

Check. Check it: 25 − 1 = 24. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 29 on the number track. The number after it is the answer.

1. Find 29. Put your finger on it.
   29
2. Move one box to the right. Each box is one more or one less.
   29 + 1 = 30
3. Write the answer.
   30

Check. Check it: 30 − 1 = 29. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Start at 20 and count on to 25. Each number is one more than the one before.

1. Start at 20. Say the first number.
   20
2. Count on to 25. Say each number, one more each time.
   20, 21, 22, 23, 24, 25
3. Write the numbers. Write them in order.
   20, 21, 22, 23, 24, 25

Check. Count back from 25 to 20. You say the same numbers in reverse. ✓

Watch out. Do not skip a number. Check each one is one more than the last.

Method. Start at 30 and count back to 26. Each number is one less than the one before.

1. Start at 30. Start with the biggest number.
   30
2. Count back to 26. Each number is one less.
   30, 29, 28, 27, 26
3. Write the numbers. Include the first and last numbers.
   30, 29, 28, 27, 26

Check. Count on from 26 to 30 to check. ✓

Watch out. Count back one at a time. Do not jump over a number.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   21, ?, 23
2. Add one to the number before each gap. That gives the missing number.
   Gap 2: 21 + 1 = 22
3. Write the missing numbers.
   22

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   27, ?, 29
2. Add one to the number before each gap. That gives the missing number.
   Gap 2: 27 + 1 = 28
3. Write the missing numbers.
   28

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   21
2. Find its name. Every number has one name.
   21 = twenty-one
3. Write the word. Write each letter in order.
   twenty-one

Check. Read the word back. It has the same number of things as 21. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “twenty-five”
2. Find the word on the list. Each word matches one number.
   twenty-five = 25
3. Write the numeral. A numeral uses digits.
   25

Check. Count 25 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Start at 20. Count on one at a time to 25. Then count how many numbers came after 20.

1. Start at 20. We start at 20.
   20
2. Count on to 25. Say each number after 20.
   21, 22, 23, 24, 25
3. Count the numbers after 20. Touch each number once.
   1, 2, 3, 4, 5
4. Write the answer.
   5

Check. Count back from 25 to 20: 5 numbers. ✓

Watch out. Do not count 20 itself. Start counting after it.

Method. Look at the first digit of each number from 20 to 29.

1. Look at 20 to 29. Each number has 2 tens.
   20, 21, ... 29
2. Check the first digit. The first digit is 2 for all of them.
   2 tens
3. Write the answer.
   Yes. The tens digit stays 2 until 29.

Check. The ones change, but the tens stay the same. ✓

Watch out. Only the ones change in the twenties.

Method. Think about the ones first, then what happens after 9 ones.

1. Look at 29. It has 2 tens and 9 ones.
   2 tens and 9 ones
2. Add one more. Nine ones and one more make one ten.
   9 + 1 = 10
3. Write the answer. Now there are 3 tens.
   Accept any answer: 29 has 2 tens and 9 ones, so one more is 3 tens, which is 30.

Check. Count 29, 30. Thirty is three tens. ✓

Watch out. Ten ones make a new ten.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   16 − 10 = 6 ones
3. Write the answer. Say it as a ten and some ones.
   16 is one ten and 6 ones

Check. Ten and 6 more makes 16: 10 + 6 = 16. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “thirteen”
2. Find the word on the list. Each word matches one number.
   thirteen = 13
3. Write the numeral. A numeral uses digits.
   13

Check. Count 13 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Say the number, then write its name in words.

1. Look at the numeral. Find it on the number list.
   15
2. Find its name. Every number has one name.
   15 = fifteen
3. Write the word. Write each letter in order.
   fifteen

Check. Read the word back. It has the same number of things as 15. ✓

Watch out. Check the spelling. Thirteen, fourteen and fifteen are different words.

Method. Find 18 on the number track. The number after it is the answer.

1. Find 18. Put your finger on it.
   18
2. Move one box to the right. Each box is one more or one less.
   18 + 1 = 19
3. Write the answer.
   19

Check. Check it: 19 − 1 = 18. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Find 14 on the number track. The number before it is the answer.

1. Find 14. Put your finger on it.
   14
2. Move one box to the left. Each box is one more or one less.
   14 − 1 = 13
3. Write the answer.
   13

Check. Check it: 13 + 1 = 14. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. The number between 11 and 13 is in the middle of them.

1. Find 11 and 13. Put your fingers on both numbers.
   11 ... 13
2. Count on one from 11. The middle number is one more than the first.
   11 + 1 = 12
3. Write the answer.
   12

Check. Count on from 12 to 13: 12 + 1 = 13. ✓

Watch out. The number between is not one of the two you started with.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   4, ?, 6, 7, ?, 9
2. Add one to the number before each gap. That gives the missing number.
   Gap 2: 4 + 1 = 5
   Gap 5: 7 + 1 = 8
3. Write the missing numbers.
   5, 8

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Start at 17 and count back to 14. Each number is one less than the one before.

1. Start at 17. Start with the biggest number.
   17
2. Count back to 14. Each number is one less.
   17, 16, 15, 14
3. Write the numbers. Include the first and last numbers.
   17, 16, 15, 14

Check. Count on from 14 to 17 to check. ✓

Watch out. Count back one at a time. Do not jump over a number.

Method. Smallest first. Look at how many tens each number has, then the ones.

1. Look at the tens of each number. More tens means a bigger number.
   19, 12, 15
2. Put the smallest first. Then put the next smallest.
   12, 15, 19
3. Write the numbers in order. Check you have not left one out.
   12, 15, 19

Check. There are 3 numbers in the question and 3 in the answer. ✓

Watch out. Compare the tens first. Only look at the ones if the tens are the same.

Method. Use the ten frame idea: one full frame, then the extras.

1. Take one full frame. A full frame is ten.
   10
2. Count the extras. Nine counters are left over.
   9 ones
3. Add them together. Ten and nine more make 19.
   10 + 9 = 19
4. Write the answer.
   Accept any answer that says 10 is one ten and 9 more ones make 19.

Check. Count on from 10: 11, 12, ... 19. ✓

Watch out. Start with the full ten, then count the ones.

Key words. A teen number is one ten and some ones, for example 13 is one ten and three ones.

Method. A teen number is one ten and some ones. Ten is one full ten frame.

1. Find the ten. Ten is one full ten frame.
   1 ten = 10
2. Count the ones left over. The ones are the extra counters.
   13 − 10 = 3 ones
3. Write the answer. Say it as a ten and some ones.
   13 is one ten and 3 ones

Check. Ten and 3 more makes 13: 10 + 3 = 13. ✓

Watch out. The “ten” always comes first. Do not count the ten frame as ones.

Method. Read the whole number word. Then find it on the number list.

1. Read the word. Read every part, including the second half of a long word.
   “eighteen”
2. Find the word on the list. Each word matches one number.
   eighteen = 18
3. Write the numeral. A numeral uses digits.
   18

Check. Count 18 things in your head, then check the numeral. ✓

Watch out. Look at the whole word. Thirteen and thirty look alike but are different.

Method. Find 16 on the number track. The number after it is the answer.

1. Find 16. Put your finger on it.
   16
2. Move one box to the right. Each box is one more or one less.
   16 + 1 = 17
3. Write the answer.
   17

Check. Check it: 17 − 1 = 16. ✓

Watch out. Move one box only. Do not write the number you started with.

Method. Each number is one more than the number before. Use the numbers you can see to find the gaps.

1. Look at the numbers around each gap. Counting on means each number is one more.
   9, ?, 11, ?, 13
2. Add one to the number before each gap. That gives the missing number.
   Gap 2: 9 + 1 = 10
   Gap 4: 11 + 1 = 12
3. Write the missing numbers.
   10, 12

Check. Read the whole line again. Every number is one more than the one before. ✓

Watch out. Check the numbers after the gap too. They should still go up by one.

Method. Start at 17 and count on to 20. Each number is one more than the one before.

1. Start at 17. Say the first number.
   17
2. Count on to 20. Say each number, one more each time.
   17, 18, 19, 20
3. Write the numbers. Write them in order.
   17, 18, 19, 20

Check. Count back from 20 to 17. You say the same numbers in reverse. ✓

Watch out. Do not skip a number. Check each one is one more than the last.

Method. Smallest first. Look at how many tens each number has, then the ones.

1. Look at the tens of each number. More tens means a bigger number.
   16, 11, 14
2. Put the smallest first. Then put the next smallest.
   11, 14, 16
3. Write the numbers in order. Check you have not left one out.
   11, 14, 16

Check. There are 3 numbers in the question and 3 in the answer. ✓

Watch out. Compare the tens first. Only look at the ones if the tens are the same.

Method. Break 14 into a ten and some ones.

1. Take one ten. A ten is 10.
   10
2. Add the ones. Four ones make the rest of 14.
   10 + 4
3. Check the total. Ten and four is fourteen.
   10 + 4 = 14
4. Write the answer.
   Yes. 14 is one ten and four ones, because 10 + 4 = 14.

Check. Count on from 10: 11, 12, 13, 14. ✓

Watch out. Start from the ten, not from 1.

Method. Count on one at a time, then look at the number after the last one.

1. Start at 25. Say each number after it.
   25
2. Count on to 28. Each number is one more.
   25, 26, 27, 28
3. Find the next number. One more than 28 is 29.
   28 + 1 = 29
4. Write the answer.
   25, 26, 27, 28. After 28 comes 29.

Check. Count back from 29 to 25 to check. ✓

Watch out. The number after 28 is 29.

Method. Start with what Lily has. Then add the 2 more ones.

1. Start with 1 ten and 6 ones. That is 16.
   10 + 6 = 16
2. Add 2 more ones. Count on from 16: 17, 18.
   16, 17, 18
3. Say it as a ten and some ones. Ten and eight ones make 18.
   10 + 8 = 18
4. Write the answer.
   18. There is one ten and eight ones.

Check. Count back 2 from 18: 17, 16. ✓

Watch out. Count on from 16, one at a time.

Method. Think about the ones digit. It goes 0 to 9 and then a new ten starts.

1. Look at 0 to 10. Ones go 0 to 9, then 10 starts a new ten.
   0 to 9, then 10
2. Look at 20 to 30. The ones go 0 to 9, then 30 starts a new ten.
   20 to 29, then 30
3. Give an example. The same pattern happens at every ten.
   29, then 30
4. Write the answer.
   Accept any answer that says the ones go 0 to 9 in each ten, then the next ten starts, for example 29 then 30.

Check. Count 9 to 10 and 29 to 30. The same pattern. ✓

Watch out. The ones start again from 0 in each new ten.