Step-by-step Maths Level 1: Tens and ones
Part of the Step-by-step Maths Level 1 counting to 20 chapter. Chapter overview · whole chapter on one page
Tens and ones
Ten things make one ten. Put ten things together first.
Then count the ones that are left over.
Here are 13 apples. There is one ten and three ones.
Key ideas
- Ten is one group of ten.
- Count the ten first, then count on.
- A ten and three ones is 13.
Method. Make a ten first. Then count the ones left over.
- Make a ten. Ten apples in one group.10
- Count the ones left over. These are the extra apples.4 ones
- Write the answer. 14
Check. Count all 14 one at a time to check. It matches.
Watch out. Start with the ten, then count on.
Method. Find how many complete tens there are, then the ones.
- Make a ten. There is one complete ten in 18.1 ten
- Count the ones. 18 - 10 = 8 ones are left.8 ones
- Write the answer. 1 ten and 8 ones
Check. Ten and eight make eighteen.
Watch out. Only one ten fits in 18, so do not say two tens.
Method. Make a ten first, then count on the rest.
- Make a ten. Ten balls in one group.10
- Count on the rest. There are six more.10 + 6
- Write the answer. 16
Check. Count back from 16: you pass one ten and six ones.
Watch out. Count the ten first, not one by one from the start.
Watch out
Watch out. 10 and 1 make 11, not 101. Write one ten and then the ones.
Exam tip
Grown-up tip. Use ten buttons or cubes. Make one group of ten and put the rest beside it. Ask: “How many tens? How many ones? How many altogether?”
Exercise 2C Tens and ones
Non-calculatorMethod. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 5 more.10 + 5 = 15
- Write the answer. 15
Check. Count all the apples one at a time to check: you get 15. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 4 more.10 + 4 = 14
- Write the answer. 14
Check. Count all the stars one at a time to check: you get 14. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 8 more.10 + 8 = 18
- Write the answer. 18
Check. Count all the balls one at a time to check: you get 18. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make groups of ten first. Then count the ones that are left.
- Make a ten. Put ten things together in a group.10 in the first group
- Count what is left. These are the ones.4 ones left over
- Write the answer. 1 ten and 4 ones
Check. Put them back together: 10 and 4 make 14.
Watch out. Count the ten first. Then count on the rest.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 4 more.10 + 4 = 14
- Write the answer. 14
Check. Count all the apples one at a time to check: you get 14. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 9 more.10 + 9 = 19
- Write the answer. 19
Check. Count all the stars one at a time to check: you get 19. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 7 more.10 + 7 = 17
- Write the answer. 17
Check. Count all the balls one at a time to check: you get 17. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make groups of ten first. Then count the ones that are left.
- Make a ten. Put ten things together in a group.10 in the first group
- Count what is left. These are the ones.9 ones left over
- Write the answer. 1 ten and 9 ones
Check. Put them back together: 10 and 9 make 19.
Watch out. Count the ten first. Then count on the rest.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 2 more.10 + 2 = 12
- Write the answer. 12
Check. Count all the apples one at a time to check: you get 12. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 1 more.10 + 1 = 11
- Write the answer. 11
Check. Count all the stars one at a time to check: you get 11. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 9 more.10 + 9 = 19
- Write the answer. 19
Check. Count all the balls one at a time to check: you get 19. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make groups of ten first. Then count the ones that are left.
- Make a ten. Put ten things together in a group.10 in the first group
- Count what is left. These are the ones.5 ones left over
- Write the answer. 1 ten and 5 ones
Check. Put them back together: 10 and 5 make 15.
Watch out. Count the ten first. Then count on the rest.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 4 more.10 + 4 = 14
- Write the answer. 14
Check. Count all the apples one at a time to check: you get 14. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 1 more.10 + 1 = 11
- Write the answer. 11
Check. Count all the stars one at a time to check: you get 11. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make a ten first. Then count on the rest.
- Make a ten. Ten things make one ten.10
- Count on the rest. There are 8 more.10 + 8 = 18
- Write the answer. 18
Check. Count all the balls one at a time to check: you get 18. ✓
Watch out. Count the first ten, then count on. Do not start from 1 again.
Method. Make groups of ten first. Then count the ones that are left.
- Make a ten. Put ten things together in a group.10 in the first group
- Count what is left. These are the ones.6 ones left over
- Write the answer. 1 ten and 6 ones
Check. Put them back together: 10 and 6 make 16.
Watch out. Count the ten first. Then count on the rest.