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KEY MATHS 7 (1)

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Section 9Percentages

Example 1

To find 12% of an amount.

First find 1% by dividing the amount by 100

Then find 12% by multiplying the answer by 12

Percent means OUT OF 100

Sale 12% cash back

Section 9PercentagesExample 2

To find 40% of £24.

First find 1%

(by dividing £24 by 100 = £0.24)

Then find 40%

(by multiplying £0.24 by 40)

= £9.60

Section 9PercentagesExample 3

To work out what percentage one number is of another

Write the number as a fraction

Change the fraction to a decimal

Change the decimal to a percentage

What percentage is 15 of 80?

1580

(15 ÷ 80)

0.1875

(0.1875 x 100)

18.75%

Section 9PercentagesExample 4

Change 4/5 to a decimal and a percentage

4/5 to a decimal

(4 ÷ 5)

0.8

0.8 to a percentage

(0.8 x 100)

80%

Section 9PercentagesExample 5

Change 80% to a fraction

80% to a fraction

(80 ÷ 100)

80100

= 80100

45

=