A percentage is a number out of 100. To find a percentage of a quantity, use its fraction or decimal.
50% of 40 = $\tfrac12$ × 40 = 20, and 25% of 40 = $\tfrac14$ × 40 = 10. Also 10% means one tenth.
Remember
- 50% = a half · 25% = a quarter · 10% = a tenth.
- "Percent of" means multiply by the fraction or decimal.