Percentages

Percentages are a way of expressing a part of a whole. 'Percent' means 'out of 100'.

What is a Percentage?

50% means 50 out of 100, which is the same as a half. 25% means 25 out of 100, which is the same as a quarter. 10% means 10 out of 100, which is the same as a tenth.

Converting Between Fractions, Decimals and Percentages

| Fraction | Decimal | Percentage | |----------|---------|------------| | 1/2 | 0.5 | 50% | | 1/4 | 0.25 | 25% | | 3/4 | 0.75 | 75% | | 1/10 | 0.1 | 10% | | 1/5 | 0.2 | 20% |

Finding Percentages of Amounts

To find 10% of a number, divide by 10.

• 10% of 80 = 8

To find 1% of a number, divide by 100.

• 1% of 200 = 2

To find other percentages, build from 10% and 1%:

• 20% of 80 = 8 x 2 = 16
• 5% of 80 = 8 / 2 = 4
• 15% of 80 = 10% + 5% = 8 + 4 = 12

Practice Problems

1. 50% of 60 = ___
2. 25% of 100 = ___
3. 10% of 250 = ___
4. 20% of 50 = ___
5. 15% of 200 = ___