From any **addition** fact such as

35 + 23 = 58

we can work out two **subtraction** facts.

Here we get

58 - 35 = 23

and

58 - 23 = 35

This is handy because we can use additions to check subtractions.

**Example 1**

Anna says that

33 - 15 = 18

Use addition to check if she is right or wrong.

**Answer**

18 + 15 = **33**

So Anna is **right**.

**Example 2**

Ben says that

54 - 15 = 31

Use addition to check if he is right or wrong.

**Answer**

31 + 15 = **46 ****not 54**

So Ben is **wrong**.