Year 8: Find the total based on a ratio

This cheat sheet will help you find the total amount when given a ratio.

Understanding Ratios

A ratio compares two amounts. It's usually written as a colon (:) between the numbers, like 2:3 or 1:4.

How to Find the Total

1. Find the Total Ratio: Add up all the numbers in the ratio.
2. Example: If the ratio is 2:3:5, add 2 + 3 + 5 = 10
3. Calculate the Value: Determine what one 'unit' in the ratio represents.
4. Example: If the total ratio is 10 and the ratio is 2:3:5, then one 'unit' is 1 (because 10 / 10 = 1).
5. Calculate the Total Amount: Multiply the 'unit' by each number in the ratio.
6. Example: 1 * 2 = 2, 1 * 3 = 3, 1 * 5 = 5. Therefore, the total is 2 + 3 + 5 = 10.

Another Example

If a recipe calls for a ratio of Flour:Sugar:Eggs = 3:2:1

Total Ratio = 3 + 2 + 1 = 6

One unit = 1 (6 / 6 = 1)

Ingredients: 3 * 1 = 3 cups of flour, 2 * 1 = 2 cups of sugar, 1 * 1 = 1 egg.