Finding a Fraction of an Amount

At some point in your exam you will be asked to find a fraction of an amount. This could be as a stand alone question or more likely, form part of a larger question. If you can remember the simple method this topic is worth two or three easy marks in the exam.

Example Question

a) Find 4 of £72.
9

b) Fred’s garden has an area of 60 m². He wants to lay decking on two fifths of his garden.
How much decking does he need?

c) Increase 90 kg by 2.
3

Solution

a)
To find a fraction of an amount remember the rule “divide by the denominator then multiple by the numerator”.
In this case we divide by 9 to find one ninth then multiply our answer by 4.

So £72 ÷ 9 = £8
Then £8 x 4 = £32

b)
We need to find 2 of 60 m².
5
First divide by the denominator: 60 ÷ 5 = 12
Then multiply by the numerator: 12 x 2 = 24 m²

So Fred lays 24m² of decking.

c)
First we need to find 2 of 90 kg.
3
90 ÷ 3 = 30
30 x 2 = 60

Finally remember to increase your original amount: 90 + 60 = 150 kg.

Test Yourself!

Find 3 of £42. 7	£
Decrease £240 by two fifths.	£

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