Step-by-step Maths Level 2: Building numbers from tens and ones
Part of the Step-by-step Maths Level 2 tens and ones chapter. Chapter overview · whole chapter on one page
Building numbers from tens and ones
To build a number, start with the tens and then add the ones.
For example, 5 tens and 2 ones make 52. Write the tens digit first.
Key ideas
- Tens first, then ones.
- The tens digit goes on the left.
- Check by splitting the number again.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.5 tens = 50
- Add the ones. The ones are added on to the tens.50 + 2 = 52
- Write the number. 52
Check. Split 52 back into tens and ones: 5 tens and 2 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.8 tens = 80
- Add the ones. The ones are added on to the tens.80 + 0 = 80
- Write the number. 80
Check. Split 80 back into tens and ones: 8 tens and 0 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Change the tens word to tens, then add the ones.
- Change the tens word. sixty is 6 tens.6 tens = 60
- Add the ones. Put the ones on the end.60 + 9 = 69
- Write the answer. 69
Check. 69 has 6 tens and 9 ones.
Watch out. Ask yourself: how many tens are in the number?
Watch out
Watch out. 3 tens and 5 ones is 35. It is not 8, and it is not 53.
Exam tip
Grown-up tip. Make numbers with tens sticks and single cubes. Ask: “How many tens, how many ones?”
Exercise 2D Practice: making numbers
Non-calculatorMethod. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.1 tens = 10
- Add the ones. The ones are added on to the tens.10 + 3 = 13
- Write the number. 13
Check. Split 13 back into tens and ones: 1 tens and 3 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.7 tens = 70
- Add the ones. The ones are added on to the tens.70 + 6 = 76
- Write the number. 76
Check. Split 76 back into tens and ones: 7 tens and 6 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.5 tens = 50
- Add the ones. The ones are added on to the tens.50 + 4 = 54
- Write the number. 54
Check. Split 54 back into tens and ones: 5 tens and 4 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Change the tens word to tens, then add the ones.
- Change the tens word. seventy is 7 tens.7 tens = 70
- Add the ones. Put the ones on the end.70 + 1 = 71
- Write the answer. 71
Check. 71 has 7 tens and 1 ones.
Watch out. Ask yourself: how many tens are in the number?
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.4 tens = 40
- Add the ones. The ones are added on to the tens.40 + 4 = 44
- Write the number. 44
Check. Split 44 back into tens and ones: 4 tens and 4 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.5 tens = 50
- Add the ones. The ones are added on to the tens.50 + 7 = 57
- Write the number. 57
Check. Split 57 back into tens and ones: 5 tens and 7 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.8 tens = 80
- Add the ones. The ones are added on to the tens.80 + 7 = 87
- Write the number. 87
Check. Split 87 back into tens and ones: 8 tens and 7 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.6 tens = 60
- Add the ones. The ones are added on to the tens.60 + 6 = 66
- Write the number. 66
Check. Split 66 back into tens and ones: 6 tens and 6 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.8 tens = 80
- Add the ones. The ones are added on to the tens.80 + 6 = 86
- Write the number. 86
Check. Split 86 back into tens and ones: 8 tens and 6 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Change the tens word to tens, then add the ones.
- Change the tens word. ten is 1 tens.1 tens = 10
- Add the ones. Put the ones on the end.10 + 3 = 13
- Write the answer. 13
Check. 13 has 1 tens and 3 ones.
Watch out. Ask yourself: how many tens are in the number?
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.3 tens = 30
- Add the ones. The ones are added on to the tens.30 + 5 = 35
- Write the number. 35
Check. Split 35 back into tens and ones: 3 tens and 5 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.7 tens = 70
- Add the ones. The ones are added on to the tens.70 + 7 = 77
- Write the number. 77
Check. Split 77 back into tens and ones: 7 tens and 7 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Change the tens word to tens, then add the ones.
- Change the tens word. seventy is 7 tens.7 tens = 70
- Add the ones. Put the ones on the end.70 + 8 = 78
- Write the answer. 78
Check. 78 has 7 tens and 8 ones.
Watch out. Ask yourself: how many tens are in the number?
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.6 tens = 60
- Add the ones. The ones are added on to the tens.60 + 3 = 63
- Write the number. 63
Check. Split 63 back into tens and ones: 6 tens and 3 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Put the tens together, then add the ones.
- Find the tens. Each ten is worth ten.8 tens = 80
- Add the ones. The ones are added on to the tens.80 + 3 = 83
- Write the number. 83
Check. Split 83 back into tens and ones: 8 tens and 3 ones.
Watch out. The ones are not added to the tens digit: 3 tens and 5 ones is 35, not 8.
Method. Change the tens word to tens, then add the ones.
- Change the tens word. ten is 1 tens.1 tens = 10
- Add the ones. Put the ones on the end.10 + 1 = 11
- Write the answer. 11
Check. 11 has 1 tens and 1 ones.
Watch out. Ask yourself: how many tens are in the number?