Ratio and Proportion (F)

Ratio is used to indicate how much of one thing there is compared to another. When talking about ratio it is a good idea to use the word PART with it, such as ‘one part juice to 5 parts water’. Then a part might be a cup, a litre, or a jugful. See how well you can work with ratio in this GCSE Maths quiz.

One of the key things about ratio is that it doesn’t include units, and so can be applied to a variety of situations. Replace the word ‘part’ with whatever unit you want – as long as you are consistent, you will mix things in the right ratio. Ratio is most commonly written using a colon to separate the two (or more) things, such as 1:5. We would read this as ‘1 part to 5 parts’.

Just like fractions, ratios can be cancelled down and written in their simplest form, by dividing each number by the Highest Common Factor (HCF).