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.
View the activity introduction for more information on the topic
Read the question aloud
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Question
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Teacher explanation