Learn how ratios work with this easy-to-understand explanation designed for 12-year-olds. Discover what ratios are, how to write them, and how to use them in everyday situations with simple examples.
A ratio is a way to compare two or more quantities. It tells us how much of one thing there is compared to another. For example, if you have 2 apples and 3 oranges, the ratio of apples to oranges is 2 to 3.
Ratios can be written in three different ways:
If the ratio is 2:3 (apples to oranges), it means that for every 2 apples, there are 3 oranges. If you had 4 apples, you would have 6 oranges, because the ratio stays the same.
Ratios are used to solve problems involving parts of a whole, mixtures, or comparisons. Here's a simple example:
Example: A recipe calls for 3 cups of flour to 2 cups of sugar. This means the ratio of flour to sugar is 3:2.
If you want to make twice as much, you double both numbers: 6 cups flour to 4 cups sugar.
If you have a ratio of 5:4 for boys to girls in a class and there are 20 boys, how many girls are there?
Step 1: Write the ratio as boys : girls = 5 : 4.
Step 2: Since there are 20 boys, find what number 20 relates to in the ratio (20 ÷ 5 = 4).
Step 3: Multiply the girls part of the ratio by 4 (4 × 4 = 16).
Answer: There are 16 girls in the class.
Ratios help us compare amounts easily. Remember to always keep the ratio the same when finding missing parts. Practice with everyday examples to get better at using ratios!