Inverse

• You will learn:

• That addition is the inverse of subtraction.

• To check your answers by using the inverse operation.

• To solve simple ‘missing number’ problems by using the inverse method.

Can you turn these addition number sentences into

subtractions?• 6+2=8

• 9+7=16

• 23+41=64

• 39+22=61

• 8-2=6

• 16-7=9

• 64-41=23

• 61-22=39

Can you make a different subtraction?

You can use this method to check your answers.

9+4= 13

Check your answer by turning it into a subtraction:

13-4= 9 or 13-9= 4

What would you do if an equation had a missing number?

+7=15

It is not a straight forward task, so use the numbers you have been

given!

+7=15

It is an addition, so start at the end and turn it into a subtraction…

15-7= 88

It is not a straight forward task, so use the numbers you have been

given!

-9=16

It is a subtraction, so start at the end and turn it into an addition…

16+9= 2525

In your books, try to solve these problems. Record the inverse calculation.

+13=29

+20=41

+17=31

+14=35

-8=14

-19=13

-27=56

-30=65

Plenary• Addition and subtraction are the inverse of each

other.

• Use this fact to help you check your answers when performing addition and subtraction calculations.

• If the first number of a problem is missing, try using the inverse method.