What are number bonds? - Year 2

Number bonds to 10

Number bonds are pairs of numbers which add up to make a certain number.

You can use number bonds to find numbers that add up to 10.

The number bonds for 10 are:

You can write a number bond as an addition number sentence, for example:

7 + 3 = 10

It doesn't matter which order you add numbers together, the total amount is the same. You can use this fact to find other number bonds.

For example, because you know that 7 + 3 is a number bond to 10, you also know that 3 + 7 is a number bond to 10.

Learn all about number bonds to 10 and 20 with this interactive activity and then put your knowledge to the test with a quiz.

You can use your knowledge of number bonds to 10 to find number bonds to 20.

Two groups of 10 make 20.

So, what would you need to add to 16 to make 20?

16 can be partitioned into a group of 10 and 6 more.

You know that 6 and 4 make a number bond to 10, so you know that you need to add 4 more to 16 to make two complete groups of 10.

Therefore, 16 and 4 make a number bond to 20.

16 + 4 = 20

4 + 16 = 20

Can you work out the other number bonds to 20?

How many counters do you need to be add to 7 to make 10?

Number bonds to 10 come in pairs.

For example, if you know that 6 + 4 = 10, you also know that 4 + 6 = 10.

If you know that 8 + 2 = 10, which number bond to 10 is a pair with this one?

You can use number bonds to 10 to work out pairs of numbers that add up to 20.

What can you add to 13 to make 20?