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!
8
+7=15
It is an addition,
so start at the end
and turn it into a
subtraction…
15-7= 8
It is not a straight forward task, so
use the numbers you have been
given!
25
-9=16
It is a subtraction,
so start at the end
and turn it into an
addition…
16+9= 25
In your books, try to solve these
problems. Record the inverse calculation.
+13=29
-8=14
+20=41
-19=13
+17=31
-27=56
+14=35
-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.