Fraction and percentage - WJEC

Fractions and percentages represent part of a whole number. They can be used to increase or decrease a value by a given proportion.

Fraction and percentage

or 'two sevenths' means two parts out of seven.

To find of a value, you must first divide by 7 to find what is worth, and then multiply by 2.

To find a fraction of an amount:

1. Divide by the
2. Multiply by the
QQuestion

Calculate of 84.

24.

1. Divide by the denominator: 84 ÷ 7 = 12
2. Multiply by the numerator: 12 x 2 = 24
QQuestion

There are 30 pupils in a class. of pupils play a musical instrument. How many do not play an instrument?

of 30 = 30 ÷ 5 = 6 pupils play a musical instrument.

This leaves 30 – 6 = 24 pupils who do not play an instrument.

Finding the original quantity

2/5 of the people on a bus are children. If there are 4 children on the bus, how many people are there in total?

of the value = 4

Divide by 2 to find

of the value = 2

Multiply by 5 to find or 1 whole

10 people in total.

QQuestion

I eat of a chocolate bar and am left with 20 squares, how many squares were there to begin with?

has been eaten, which leaves

= 20 squares (now divide by 5)

= 4 squares (now multiply by 8)

1 whole = 32 squares.

QQuestion

Louis’ father increases his pocket money by . He now receives £26 a month. How much was he receiving originally?

£19.50

= £26 (now divide by 4)

= £6.50 (now multiply by 3)

1 whole = £19.50