Addition and subtraction** family facts** normally come in **FOURS**.

There are** TWO addition facts** and **TWO subtraction facts**.

If we know just one of them, we can always work out the other three.

If we know the **addition** **fact** that

3 + 5 = 8

we can say that the other **addition fact** in this family is

5 + 3 = 8

The **subtraction** **facts** in this family will be

8 - 5 = 3

and

8 - 3 = 5

**Example**

What are the three related family facts for...?

15 + 18 = 33

**Answer**

For the other **addition fact**, just reverse the first two numbers.

The other **addition fact** in this family is

18 + 15 = 33

For the **subtraction fact**, we start with the biggest number.

The **subtraction facts** in this family will be

33 - 15 = 18

and

33 - 18 = 15