What is a number sentence?

Children start learning how to write addition and subtraction number sentences in Year 1. They will probably start learning about addition by making two groups (for example: 5 bananas and 2 apples) and putting them together. They then develop towards working out how to write these numbers and arrange them with the symbols + and = to make a number sentence that makes sense.

In Year 2, children start to write number sentences for multiplication and division, so they need to understand the symbols: x and ÷ and be able to write them.  

Children may also come across number sentences with gaps in them. In Key Stage 1 they may come across something like this:

and be asked to work out what goes in the gap.

These will get progressively harder in Key Stage 2, for example:

Sometimes children will be given number sentences where there are two operations on each side, for example:

Here, they need to understand that since the left hand side equals 16, the right hand side has to equal the same amount, since 20 - 4 = 16, the number in the gap should be 4.

They may be given a number sentence like the one above, but where there is not one answer to put in the gap:

Here, it may be a good idea to try a number out in the first gap, for example, 10:

10 + 20 + 10 = 40

We know that 5 x 8 = 40, so 8 could then go in the other gap.

A teacher may then ask children to find as many other possibilities as they can.