A fraction is made up of one number over another number, e.g. 3
‘three over four’ or even ‘3 divided by 4’.
When one number is over another number, this means we must divide the top number by the bottom number.
Numerator The top half of the fraction The number of parts you have
A line separates the numerator and the denominator
3 4
To convert a fraction to a percentage
The easiest way to convert a fraction to a percentage is to multiply the fraction by 100%.
Worked example 1 Convert the following fractions to (i) a decimal and (ii) a percentage. (a) 2
__ 5
Solution (a)
(i) (b) 3
__ 4
(b) (i) (ii)
Converting between fractions, decimals and percentages will be revisited in Unit 5.
Does the shape of a fraction look familiar? It’s the same as the symbol for division, ÷ . The top dot stands in for the numerator, and the bottom dot stands in for the denominator.
In mathematical language, we must divide the numerator by the denominator.
Fraction The whole thing
Denominator
The bottom half of the fraction The number of parts in a whole
Worked example 2
There are 24 students in a class: 18 boys and 6 girls. If a student is picked at random, fi nd the chance that the student picked is: (i) a boy
(ii) a girl Give your answer as a fraction, a decimal and a percentage. Solution (ii)