Use the Inverse Operation to Find the Answer

In this activity, we will be finding the missing number in a calculation.

Example

Find the number that makes the calculation correct.

332 + __ = 900

Answer

The opposite (inverse) of adding is subtracting.

So we work out 900 - 332 = 568

Here is a simpler example:

400 + ___ = 600

The inverse operation is:

600 - 400 = 200

The answer is 200

Does that make sense?

Let's practise this skill in the following questions.