Using inverse operations to find the missing number
22 October 2026
When children are faced with a missing number in an equation, it helps to know that every operation has an opposite. This makes it much easier to work out what the missing value should be.
Example question
14 +? = 22
Step 1: The inverse of addition is subtraction.
Step 2: Subtract 14 from 22. 22 - 14 = 8
The correct answer is 8.
Click or tap on the number line to answer
Key insight: If your child can spot which operation is being used, they can use the inverse operation to find the answer. This approach works for many similar questions, so your child can feel confident when practising more missing number problems on maths.com uk.
