ratio

Everyday

1. A ratio compares two amounts by how many times one fits into the other. If there are 2 cats for every 3 dogs, the ratio is 2 to 3. tree →
2. A ratio can compare more than two amounts, like 1:2:3. tree →
3. Ratio can also mean reason or sense, the ability to understand something clearly. tree →

In the lessons

In maths: a comparison of two counts, written 2:3 or «2 to 3»; problems share a total in a ratio or find one part; «for every». In science and cooking: mixing in a ratio (2 parts water to 1 part juice). In art: mixing paint colours. In everyday life: maps and models use a scale ratio, like 1:100.

Examples

• The ratio of boys to girls is 3 to 4. tree →
• There are 12 boys, so there are 16 girls. tree →
• Mix paint in the ratio 2:1. tree →
• Share 30 sweets in the ratio 1:2. tree →
• For every 2 cups of flour, add 1 cup of milk. tree →
• The model car is made at a ratio of 1:20. tree →
• The ratio of wheels to bikes is 2:1. tree →
• Mix squash and water in the ratio 1 to 4. tree →
• But Fionn would see and know, or he would under-stand a decent ratio of his visions. tree →

Note

A ratio is about parts: add the parts to get the whole number of parts, then divide the total by it. Example: 30 in the ratio 1:2 → 3 parts, 30 ÷ 3 = 10 per part → 10 and 20. Trap: the order counts; «boys to girls 3:4» is not the same as 4:3. Trap: 3:4 means 3 out of 7 are boys, not 3 out of 4. Plural: ratios.