A ratio is a method in maths that is used to compare two (or more) quantities.
So, for example, if I had 3 red balls, 9 blue balls and 10 green balls, the ratio of red to blue balls would be 3:9:10
One thing that is vital in ratio is remembering that the order is important.
Cancelling a ratio
When you are trying to cancel a ratio, the rules are the same as if you were trying to cancel a fraction. You need to find the Highest Common Factor (HCF) of all the numbers and then divide by that.
Example 1: Cancel 9:3:6 to its simplest form.
The Highest Common Factor of 9,3 and 6 is 3, so we divide each part by 3
Example 2: Simplify 25:85:15 as far as possible.
The HCG of 25, 85 and 15 is 5, so we divide each part by 5.
Example 3: Write £2 to 30p to 45p as a ratio in its simplest form.
The key thing to notice here is that the units aren't the same so we have to change this.
Remember as well that the order for the ratio must be the same as in the question
£2 : 30 p : 45p
200 p : 30 p : 45p
Now we can cancel down, we can also get rid of the units now they are the same. The HCF here is 5, so we divide by 5.
40: 6: 9