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Inverse operations are really important in maths.
For example, when you have to solve equations (which is a huge topic), you can't do it without these inverse operations.
Inverse operations require us to understand the opposite operation of what is shown.
The opposite of + is -
The opposite of - is +
The opposite of x is ÷
The opposite of ÷ is x
e.g. What is the opposite of +7?
e.g. What is the opposite of dividing by 2?
Multiplying by 2
Let's put an inverse operation into context now...
I add 7 and then multiply by 2.
If my answer is 18, what was my original number?
This one is a bit more challenging.
We have two operations: + 7 and x 2.
The inverse operations for these would be - 7 and ÷ 2.
But which operation do we use first?
If we are doing the opposite, we are moving backwards through the sum.
In the question, we added 7 first then multiplied by 2.
When we are doing the inverse, we swap this order as well.
So to solve this we divide by 2 first, then subtract 7:
18 ÷ 2 = 9
9 - 7 = 2
The original starting number was 2.
Now it's your turn to have a go!
In this activity, you will find inverse operations and use these to work backwards from outcomes to starting points.