Counting to 100
By the end of this chapter you will be able to
- Count forwards and backwards to 100
- Count in 2s, 5s and 10s
- Write numbers from 20 to 100 in numerals and words
- Count on and back from any number
You should already know
- Counting to 20 (Level 1)
Where this leads
- Tens and ones (Level 2, Chapter 2)
- Comparing and ordering to 100 (Chapter 3)
Step-by-step practice: maths (Level 2). Small steps, repeated until fluent. Content: Count forwards and backwards from 0 to 100, Count forwards and backwards from any number up to 100, Count in ones, and in steps of 2, 5 and 10, Read and write numerals and number words from 20 to 100, Say the number before and the number after any number up to 100.
Exercise P Do you remember?
Non-calculatorMethod. The number after is the next number when we count on one.
- Start at the number. We begin where we are.8
- Count on one. The next number is one more.8 + 1 = 9
- Write the answer. 9
Check. Count back one from 9: you reach 8. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.16
- Count on one. The next number is one more.16 + 1 = 17
- Write the answer. 17
Check. Count back one from 17: you reach 16. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.19
- Count back one. The number before is one less.19 - 1 = 18
- Write the answer. 18
Check. Count on one from 18: you reach 19. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.11
- Count back one. The number before is one less.11 - 1 = 10
- Write the answer. 10
Check. Count on one from 10: you reach 11. It works.
Watch out. The number before is one less. Do not say the same number.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.ten = 1 tens
- Find the ones word. The ones word tells us the ones digit.four = 4
- Write the numeral. Tens digit first, then ones digit.14
Check. Say 14 as a number name to check: fourteen.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Counting forwards to 100
We count forwards one number at a time. Each number is one more than the number before.
To find the number after, add one. Go to the next number on the count.
Key ideas
- Counting forwards means each number is one more.
- The number after 39 is 40.
- Count to 100 and stop there.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.47
- Count on one. The next number is one more.47 + 1 = 48
- Write the answer. 48
Check. Count back one from 48: you reach 47. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.69
- Count on one. The next number is one more.69 + 1 = 70
- Write the answer. 70
Check. Count back one from 70: you reach 69. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.99
- Count on one. The next number is one more.99 + 1 = 100
- Write the answer. 100
Check. Count back one from 100: you reach 99. It works.
Watch out. The number after is one bigger, not the same number again.
Watch out
Watch out. Thirty and forty are not the same. After 39 comes 40, not 30.
Exam tip
Grown-up tip. Count forwards from 0 to 100 in tens, then ones. Aim for a count without stopping. Ask: “What comes after 59?”
Exercise 1A Practice: the number after
Non-calculatorMethod. The number after is the next number when we count on one.
- Start at the number. We begin where we are.94
- Count on one. The next number is one more.94 + 1 = 95
- Write the answer. 95
Check. Count back one from 95: you reach 94. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.41
- Count on one. The next number is one more.41 + 1 = 42
- Write the answer. 42
Check. Count back one from 42: you reach 41. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.38
- Count on one. The next number is one more.38 + 1 = 39
- Write the answer. 39
Check. Count back one from 39: you reach 38. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.72
- Count on one. The next number is one more.72 + 1 = 73
- Write the answer. 73
Check. Count back one from 73: you reach 72. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.43
- Count on one. The next number is one more.43 + 1 = 44
- Write the answer. 44
Check. Count back one from 44: you reach 43. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.51
- Count on one. The next number is one more.51 + 1 = 52
- Write the answer. 52
Check. Count back one from 52: you reach 51. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.2
- Count on one. The next number is one more.2 + 1 = 3
- Write the answer. 3
Check. Count back one from 3: you reach 2. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.58
- Count on one. The next number is one more.58 + 1 = 59
- Write the answer. 59
Check. Count back one from 59: you reach 58. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.57
- Count on one. The next number is one more.57 + 1 = 58
- Write the answer. 58
Check. Count back one from 58: you reach 57. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.93
- Count on one. The next number is one more.93 + 1 = 94
- Write the answer. 94
Check. Count back one from 94: you reach 93. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.32
- Count on one. The next number is one more.32 + 1 = 33
- Write the answer. 33
Check. Count back one from 33: you reach 32. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.5
- Count on one. The next number is one more.5 + 1 = 6
- Write the answer. 6
Check. Count back one from 6: you reach 5. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.0
- Count on one. The next number is one more.0 + 1 = 1
- Write the answer. 1
Check. Count back one from 1: you reach 0. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.4
- Count on one. The next number is one more.4 + 1 = 5
- Write the answer. 5
Check. Count back one from 5: you reach 4. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.77
- Count on one. The next number is one more.77 + 1 = 78
- Write the answer. 78
Check. Count back one from 78: you reach 77. It works.
Watch out. The number after is one bigger, not the same number again.
Method. Count on from 39 one step at a time.
- Start at 39. It is the number we begin with.39
- Count on one. The number after 39 is 40, not 30.39 + 1 = 40
- Compare with Sam. Thirty is before 39, not after it.No, 40
Check. Count back from 40 one step: 40, 39. That is correct.
Watch out. Thirty comes before 39, so it cannot come after it.
Counting backwards
We can also count backwards. Each number is one less than the number after it.
To find the number before, take one away.
Key ideas
- Counting backwards means each number is one less.
- The number before 60 is 59.
- Do not say the number you start with again.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.60
- Count back one. The number before is one less.60 - 1 = 59
- Write the answer. 59
Check. Count on one from 59: you reach 60. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.81
- Count back one. The number before is one less.81 - 1 = 80
- Write the answer. 80
Check. Count on one from 80: you reach 81. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.31
- Count back one. The number before is one less.31 - 1 = 30
- Write the answer. 30
Check. Count on one from 30: you reach 31. It works.
Watch out. The number before is one less. Do not say the same number.
Watch out
Watch out. The number before 40 is 39. Do not say 30.
Exam tip
Grown-up tip. Count back from 20 to 0 on the stairs, one step at a time. Then try from 100.
Exercise 1B Practice: the number before
Non-calculatorMethod. The number before is the number we say just before this one.
- Start at the number. We begin where we are.64
- Count back one. The number before is one less.64 - 1 = 63
- Write the answer. 63
Check. Count on one from 63: you reach 64. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.69
- Count back one. The number before is one less.69 - 1 = 68
- Write the answer. 68
Check. Count on one from 68: you reach 69. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.55
- Count back one. The number before is one less.55 - 1 = 54
- Write the answer. 54
Check. Count on one from 54: you reach 55. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.74
- Count back one. The number before is one less.74 - 1 = 73
- Write the answer. 73
Check. Count on one from 73: you reach 74. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.10
- Count back one. The number before is one less.10 - 1 = 9
- Write the answer. 9
Check. Count on one from 9: you reach 10. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.13
- Count back one. The number before is one less.13 - 1 = 12
- Write the answer. 12
Check. Count on one from 12: you reach 13. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.26
- Count back one. The number before is one less.26 - 1 = 25
- Write the answer. 25
Check. Count on one from 25: you reach 26. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.85
- Count back one. The number before is one less.85 - 1 = 84
- Write the answer. 84
Check. Count on one from 84: you reach 85. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.1
- Count back one. The number before is one less.1 - 1 = 0
- Write the answer. 0
Check. Count on one from 0: you reach 1. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.63
- Count back one. The number before is one less.63 - 1 = 62
- Write the answer. 62
Check. Count on one from 62: you reach 63. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.94
- Count back one. The number before is one less.94 - 1 = 93
- Write the answer. 93
Check. Count on one from 93: you reach 94. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.11
- Count back one. The number before is one less.11 - 1 = 10
- Write the answer. 10
Check. Count on one from 10: you reach 11. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.97
- Count back one. The number before is one less.97 - 1 = 96
- Write the answer. 96
Check. Count on one from 96: you reach 97. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.65
- Count back one. The number before is one less.65 - 1 = 64
- Write the answer. 64
Check. Count on one from 64: you reach 65. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.17
- Count back one. The number before is one less.17 - 1 = 16
- Write the answer. 16
Check. Count on one from 16: you reach 17. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.44
- Count back one. The number before is one less.44 - 1 = 43
- Write the answer. 43
Check. Count on one from 43: you reach 44. It works.
Watch out. The number before is one less. Do not say the same number.
Counting in steps of 2, 5 and 10
We can count in steps. Instead of going up by one, we go up by 2, 5 or 10.
Look at the step between two numbers. Then count on the same step to fill the gaps.
Key ideas
- Counting in 10s: 10, 20, 30 ...
- Counting in 5s: 5, 10, 15 ...
- Counting in 2s: 2, 4, 6 ...
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.40, 45, 50
- Count on in steps to fill the gaps. Add the step to the number before each gap.40, 45, 50, 55, 60
- Write the missing numbers. 45 and 55
Check. Check the whole row: 40, 45, 50, 55, 60. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.62, 64, 66
- Count on in steps to fill the gaps. Add the step to the number before each gap.62, 64, 66, 68, 70
- Write the missing numbers. 64 and 68
Check. Check the whole row: 62, 64, 66, 68, 70. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.50, 60, 70
- Count on in steps to fill the gaps. Add the step to the number before each gap.50, 60, 70, 80, 90
- Write the missing numbers. 70 and 90
Check. Check the whole row: 50, 60, 70, 80, 90. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Watch out
Watch out. In steps of 5 the numbers end in 0 or 5. Do not write 42 in a count in 5s.
Exam tip
Grown-up tip. Count in 10s on the hundred square. Then count in 5s by touching the 5s and 10s.
Exercise 1C Practice: counting in 2s, 5s and 10s
Non-calculatorMethod. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.75, 80, 85
- Count on in steps to fill the gaps. Add the step to the number before each gap.75, 80, 85, 90, 95
- Write the missing numbers. 85 and 95
Check. Check the whole row: 75, 80, 85, 90, 95. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.0, 10, 20
- Count on in steps to fill the gaps. Add the step to the number before each gap.0, 10, 20, 30, 40
- Write the missing numbers. 10 and 30
Check. Check the whole row: 0, 10, 20, 30, 40. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.75, 80, 85
- Count on in steps to fill the gaps. Add the step to the number before each gap.75, 80, 85, 90, 95
- Write the missing numbers. 80 and 90
Check. Check the whole row: 75, 80, 85, 90, 95. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.50, 55, 60
- Count on in steps to fill the gaps. Add the step to the number before each gap.50, 55, 60, 65, 70
- Write the missing numbers. 55 and 65
Check. Check the whole row: 50, 55, 60, 65, 70. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.40, 50, 60
- Count on in steps to fill the gaps. Add the step to the number before each gap.40, 50, 60, 70, 80
- Write the missing numbers. 50 and 70
Check. Check the whole row: 40, 50, 60, 70, 80. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.40, 45, 50
- Count on in steps to fill the gaps. Add the step to the number before each gap.40, 45, 50, 55, 60
- Write the missing numbers. 50 and 60
Check. Check the whole row: 40, 45, 50, 55, 60. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.0, 5, 10
- Count on in steps to fill the gaps. Add the step to the number before each gap.0, 5, 10, 15, 20
- Write the missing numbers. 0 and 10
Check. Check the whole row: 0, 5, 10, 15, 20. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.60, 62, 64
- Count on in steps to fill the gaps. Add the step to the number before each gap.60, 62, 64, 66, 68
- Write the missing numbers. 60 and 64
Check. Check the whole row: 60, 62, 64, 66, 68. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.20, 30, 40
- Count on in steps to fill the gaps. Add the step to the number before each gap.20, 30, 40, 50, 60
- Write the missing numbers. 20 and 40
Check. Check the whole row: 20, 30, 40, 50, 60. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.38, 40, 42
- Count on in steps to fill the gaps. Add the step to the number before each gap.38, 40, 42, 44, 46
- Write the missing numbers. 42 and 46
Check. Check the whole row: 38, 40, 42, 44, 46. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.32, 34, 36
- Count on in steps to fill the gaps. Add the step to the number before each gap.32, 34, 36, 38, 40
- Write the missing numbers. 34 and 38
Check. Check the whole row: 32, 34, 36, 38, 40. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.35, 40, 45
- Count on in steps to fill the gaps. Add the step to the number before each gap.35, 40, 45, 50, 55
- Write the missing numbers. 45 and 55
Check. Check the whole row: 35, 40, 45, 50, 55. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.46, 48, 50
- Count on in steps to fill the gaps. Add the step to the number before each gap.46, 48, 50, 52, 54
- Write the missing numbers. 46 and 50
Check. Check the whole row: 46, 48, 50, 52, 54. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.20, 30, 40
- Count on in steps to fill the gaps. Add the step to the number before each gap.20, 30, 40, 50, 60
- Write the missing numbers. 30 and 50
Check. Check the whole row: 20, 30, 40, 50, 60. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.50, 60, 70
- Count on in steps to fill the gaps. Add the step to the number before each gap.50, 60, 70, 80, 90
- Write the missing numbers. 60 and 80
Check. Check the whole row: 50, 60, 70, 80, 90. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.30, 35, 40
- Count on in steps to fill the gaps. Add the step to the number before each gap.30, 35, 40, 45, 50
- Write the missing numbers. 40 and 50
Check. Check the whole row: 30, 35, 40, 45, 50. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Numbers from 20 to 100
Numbers from 20 to 100 have a tens part and a ones part.
The tens word tells you the tens digit. For example, forty is 4 tens, so it is 40.
Key ideas
- The tens digit is written first.
- Twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety.
- A hyphen joins the tens word and the ones word, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.sixty = 6 tens
- Find the ones word. The ones word tells us the ones digit.three = 3
- Write the numeral. Tens digit first, then ones digit.63
Check. Say 63 as a number name to check: sixty-three.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.2 tens = twenty
- Find the ones part. The ones digit gives the last word.9 ones: nine ones
- Write the name. Put a hyphen between the tens word and the ones word.twenty-nine
Check. Read the name back: twenty-nine is 29.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.8 tens = eighty
- Find the ones part. The ones digit gives the last word.0 ones: no ones, so there is no hyphen
- Write the name. Put a hyphen between the tens word and the ones word.eighty
Check. Read the name back: eighty is 80.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Watch out
Watch out. Thirteen is 13, but thirty is 30. Check the tens digit first.
Exam tip
Grown-up tip. Say the number names out loud. Count in tens, then add the ones. Write the number as a numeral.
Exercise 1D Practice: numerals and words
Non-calculatorMethod. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.twenty = 2 tens
- Find the ones word. The ones word tells us the ones digit.two = 2
- Write the numeral. Tens digit first, then ones digit.22
Check. Say 22 as a number name to check: twenty-two.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.3 tens = thirty
- Find the ones part. The ones digit gives the last word.5 ones: five ones
- Write the name. Put a hyphen between the tens word and the ones word.thirty-five
Check. Read the name back: thirty-five is 35.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.twenty = 2 tens
- Find the ones word. The ones word tells us the ones digit.eight = 8
- Write the numeral. Tens digit first, then ones digit.28
Check. Say 28 as a number name to check: twenty-eight.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.3 tens = thirty
- Find the ones part. The ones digit gives the last word.9 ones: nine ones
- Write the name. Put a hyphen between the tens word and the ones word.thirty-nine
Check. Read the name back: thirty-nine is 39.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.seventy = 7 tens
- Find the ones word. The ones word tells us the ones digit.one = 1
- Write the numeral. Tens digit first, then ones digit.71
Check. Say 71 as a number name to check: seventy-one.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.5 tens = fifty
- Find the ones part. The ones digit gives the last word.6 ones: six ones
- Write the name. Put a hyphen between the tens word and the ones word.fifty-six
Check. Read the name back: fifty-six is 56.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.thirty = 3 tens
- Find the ones word. The ones word tells us the ones digit.six = 6
- Write the numeral. Tens digit first, then ones digit.36
Check. Say 36 as a number name to check: thirty-six.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.2 tens = twenty
- Find the ones part. The ones digit gives the last word.1 ones: one ones
- Write the name. Put a hyphen between the tens word and the ones word.twenty-one
Check. Read the name back: twenty-one is 21.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.sixty = 6 tens
- Find the ones word. The ones word tells us the ones digit.two = 2
- Write the numeral. Tens digit first, then ones digit.62
Check. Say 62 as a number name to check: sixty-two.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.6 tens = sixty
- Find the ones part. The ones digit gives the last word.4 ones: four ones
- Write the name. Put a hyphen between the tens word and the ones word.sixty-four
Check. Read the name back: sixty-four is 64.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.twenty = 2 tens
- Find the ones word. The ones word tells us the ones digit.seven = 7
- Write the numeral. Tens digit first, then ones digit.27
Check. Say 27 as a number name to check: twenty-seven.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.4 tens = forty
- Find the ones part. The ones digit gives the last word.4 ones: four ones
- Write the name. Put a hyphen between the tens word and the ones word.forty-four
Check. Read the name back: forty-four is 44.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.eighty = 8 tens
- Find the ones word. The ones word tells us the ones digit.eight = 8
- Write the numeral. Tens digit first, then ones digit.88
Check. Say 88 as a number name to check: eighty-eight.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.6 tens = sixty
- Find the ones part. The ones digit gives the last word.0 ones: no ones, so there is no hyphen
- Write the name. Put a hyphen between the tens word and the ones word.sixty
Check. Read the name back: sixty is 60.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.twenty = 2 tens
- Find the ones word. The ones word tells us the ones digit.zero = 0
- Write the numeral. Tens digit first, then ones digit.20
Check. Say 20 as a number name to check: twenty.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.5 tens = fifty
- Find the ones part. The ones digit gives the last word.0 ones: no ones, so there is no hyphen
- Write the name. Put a hyphen between the tens word and the ones word.fifty
Check. Read the name back: fifty is 50.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Counting on from any number
You do not have to start at zero. Start at the number you are given.
Count on to go up. Count back to go down. The number line helps you to see the jumps.
Key ideas
- Start at the number you are given.
- Count on to go up, count back to go down.
- Say each new number as you go.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.46
- Count on by 7. Say each new number as we go.46 + 7 = 53
- Write the answer. This is the last number we said.53
Check. Count back 7 from 53 to check. You arrive at 46.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.72
- Count back by 5. Say each number we pass.72 - 5 = 67
- Write the answer. This is the last number we said.67
Check. Count on 5 from 67 to check. You arrive at 72.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.38
- Count on by 9. Say each new number as we go.38 + 9 = 47
- Write the answer. This is the last number we said.47
Check. Count back 9 from 47 to check. You arrive at 38.
Watch out. Count on from the number you start with, do not start again from zero.
Watch out
Watch out. When you count on 7 from 46, you do not start again at 1. Begin at 46.
Exam tip
Grown-up tip. Use a number line or a hundred square. Ask the child to jump on the number line with a finger.
Exercise 1E Practice: counting on and back
Non-calculatorMethod. Start at the number and count back in steps.
- Start at the first number. It is where we begin.66
- Count back by 4. Say each number we pass.66 - 4 = 62
- Write the answer. This is the last number we said.62
Check. Count on 4 from 62 to check. You arrive at 66.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.88
- Count on by 6. Say each new number as we go.88 + 6 = 94
- Write the answer. This is the last number we said.94
Check. Count back 6 from 94 to check. You arrive at 88.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.52
- Count back by 6. Say each number we pass.52 - 6 = 46
- Write the answer. This is the last number we said.46
Check. Count on 6 from 46 to check. You arrive at 52.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.42
- Count back by 7. Say each number we pass.42 - 7 = 35
- Write the answer. This is the last number we said.35
Check. Count on 7 from 35 to check. You arrive at 42.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.40
- Count on by 6. Say each new number as we go.40 + 6 = 46
- Write the answer. This is the last number we said.46
Check. Count back 6 from 46 to check. You arrive at 40.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.34
- Count on by 2. Say each new number as we go.34 + 2 = 36
- Write the answer. This is the last number we said.36
Check. Count back 2 from 36 to check. You arrive at 34.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.73
- Count back by 7. Say each number we pass.73 - 7 = 66
- Write the answer. This is the last number we said.66
Check. Count on 7 from 66 to check. You arrive at 73.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.24
- Count back by 8. Say each number we pass.24 - 8 = 16
- Write the answer. This is the last number we said.16
Check. Count on 8 from 16 to check. You arrive at 24.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.84
- Count on by 4. Say each new number as we go.84 + 4 = 88
- Write the answer. This is the last number we said.88
Check. Count back 4 from 88 to check. You arrive at 84.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.17
- Count on by 7. Say each new number as we go.17 + 7 = 24
- Write the answer. This is the last number we said.24
Check. Count back 7 from 24 to check. You arrive at 17.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.24
- Count back by 5. Say each number we pass.24 - 5 = 19
- Write the answer. This is the last number we said.19
Check. Count on 5 from 19 to check. You arrive at 24.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.90
- Count on by 4. Say each new number as we go.90 + 4 = 94
- Write the answer. This is the last number we said.94
Check. Count back 4 from 94 to check. You arrive at 90.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.64
- Count on by 2. Say each new number as we go.64 + 2 = 66
- Write the answer. This is the last number we said.66
Check. Count back 2 from 66 to check. You arrive at 64.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.11
- Count on by 3. Say each new number as we go.11 + 3 = 14
- Write the answer. This is the last number we said.14
Check. Count back 3 from 14 to check. You arrive at 11.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.15
- Count back by 8. Say each number we pass.15 - 8 = 7
- Write the answer. This is the last number we said.7
Check. Count on 8 from 7 to check. You arrive at 15.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.50
- Count on by 4. Say each new number as we go.50 + 4 = 54
- Write the answer. This is the last number we said.54
Check. Count back 4 from 54 to check. You arrive at 50.
Watch out. Count on from the number you start with, do not start again from zero.
Chapter summary
| Skill | Method |
|---|---|
| Count forwards | Add one to get the number after |
| Count backwards | Take one away to get the number before |
| Steps of 2, 5 and 10 | Find the step, then count on in that step |
| Numerals and words | Tens word gives the tens digit, then the ones |
| Count on and back | Start at the number you are given and jump |
Can you…?
- I can count forwards and backwards to 100
- I can say the number before and after any number up to 100
- I can count in 2s, 5s and 10s and fill in the gaps
- I can write numbers from 20 to 100 in numerals and in words
- I can count on and back from any number
Key terms
- after
- the next number on the count, one more
- before
- the number just before, one less
- step
- the size of the jump, for example 5 in 5, 10, 15
- tens digit
- the digit that shows how many tens, for example the 4 in 46
Exercise 1Z Check-up
Non-calculatorMethod. Start at the number and count on in steps.
- Start at the first number. It is where we begin.43
- Count on by 6. Say each new number as we go.43 + 6 = 49
- Write the answer. This is the last number we said.49
Check. Count back 6 from 49 to check. You arrive at 43.
Watch out. Count on from the number you start with, do not start again from zero.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.97
- Count back by 3. Say each number we pass.97 - 3 = 94
- Write the answer. This is the last number we said.94
Check. Count on 3 from 94 to check. You arrive at 97.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.90
- Count on by 7. Say each new number as we go.90 + 7 = 97
- Write the answer. This is the last number we said.97
Check. Count back 7 from 97 to check. You arrive at 90.
Watch out. Count on from the number you start with, do not start again from zero.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.48, 50, 52
- Count on in steps to fill the gaps. Add the step to the number before each gap.48, 50, 52, 54, 56
- Write the missing numbers. 50 and 54
Check. Check the whole row: 48, 50, 52, 54, 56. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.2, 4, 6
- Count on in steps to fill the gaps. Add the step to the number before each gap.2, 4, 6, 8, 10
- Write the missing numbers. 2 and 6
Check. Check the whole row: 2, 4, 6, 8, 10. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.85
- Count back one. The number before is one less.85 - 1 = 84
- Write the answer. 84
Check. Count on one from 84: you reach 85. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.86
- Count back one. The number before is one less.86 - 1 = 85
- Write the answer. 85
Check. Count on one from 85: you reach 86. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.66
- Count back one. The number before is one less.66 - 1 = 65
- Write the answer. 65
Check. Count on one from 65: you reach 66. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The numbers go up in steps of 2. Find the step first.
- Find the step. Each number is 2 more than the one before.12, 14, 16
- Count on in steps to fill the gaps. Add the step to the number before each gap.12, 14, 16, 18, 20
- Write the missing numbers. 16 and 20
Check. Check the whole row: 12, 14, 16, 18, 20. Each step is 2.
Watch out. Do not count in ones. Count in steps of 2.
Method. Say the tens part, then the ones part.
- Find the tens part. The tens digit gives the tens word.9 tens = ninety
- Find the ones part. The ones digit gives the last word.2 ones: two ones
- Write the name. Put a hyphen between the tens word and the ones word.ninety-two
Check. Read the name back: ninety-two is 92.
Watch out. Use a hyphen between tens and ones, for example forty-six.
Total 19 marks. Allow about 19 minutes.
Exercise 1X Practice test questions
Non-calculatorMethod. The numbers go up in steps of 10. Find the step first.
- Find the step. Each number is 10 more than the one before.30, 40, 50
- Count on in steps to fill the gaps. Add the step to the number before each gap.30, 40, 50, 60, 70
- Write the missing numbers. 30 and 50
Check. Check the whole row: 30, 40, 50, 60, 70. Each step is 10.
Watch out. Do not count in ones. Count in steps of 10.
Method. The number after is the next number when we count on one.
- Start at the number. We begin where we are.59
- Count on one. The next number is one more.59 + 1 = 60
- Write the answer. 60
Check. Count back one from 60: you reach 59. It works.
Watch out. The number after is one bigger, not the same number again.
Method. The numbers go up in steps of 5. Find the step first.
- Find the step. Each number is 5 more than the one before.75, 80, 85
- Count on in steps to fill the gaps. Add the step to the number before each gap.75, 80, 85, 90, 95
- Write the missing numbers. 80 and 90
Check. Check the whole row: 75, 80, 85, 90, 95. Each step is 5.
Watch out. Do not count in ones. Count in steps of 5.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.92
- Count back by 3. Say each number we pass.92 - 3 = 89
- Write the answer. This is the last number we said.89
Check. Count on 3 from 89 to check. You arrive at 92.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. Start at the number and count back in steps.
- Start at the first number. It is where we begin.67
- Count back by 3. Say each number we pass.67 - 3 = 64
- Write the answer. This is the last number we said.64
Check. Count on 3 from 64 to check. You arrive at 67.
Watch out. Count back from the number you start with. Do not count the starting number again.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.33
- Count back one. The number before is one less.33 - 1 = 32
- Write the answer. 32
Check. Count on one from 32: you reach 33. It works.
Watch out. The number before is one less. Do not say the same number.
Method. The number before is the number we say just before this one.
- Start at the number. We begin where we are.95
- Count back one. The number before is one less.95 - 1 = 94
- Write the answer. 94
Check. Count on one from 94: you reach 95. It works.
Watch out. The number before is one less. Do not say the same number.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.ninety = 9 tens
- Find the ones word. The ones word tells us the ones digit.nine = 9
- Write the numeral. Tens digit first, then ones digit.99
Check. Say 99 as a number name to check: ninety-nine.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Find the tens first, then the ones.
- Find the tens word. The tens word tells us how many tens.seventy = 7 tens
- Find the ones word. The ones word tells us the ones digit.seven = 7
- Write the numeral. Tens digit first, then ones digit.77
Check. Say 77 as a number name to check: seventy-seven.
Watch out. Write the tens digit first. Seventy-four is 74, not 47.
Method. Start at the number and count on in steps.
- Start at the first number. It is where we begin.79
- Count on by 7. Say each new number as we go.79 + 7 = 86
- Write the answer. This is the last number we said.86
Check. Count back 7 from 86 to check. You arrive at 79.
Watch out. Count on from the number you start with, do not start again from zero.