25% = 25/100 = 1/4 = 0.25. To find 25% of 80, multiply 0.25 × 80 = 20.
Work backward
If 12 is 30% of a number, write 0.30 × whole = 12. The whole is 12 ÷ 0.30 = 40.
Practice
- Find 10% of 250.
- Find 15% of 60.
- 18 is what percent of 72?
- 20 is 40% of what number?
- A fictional $50 item is reduced by 20%. What is its new price before any other charges?
Show answers and reasoning
- 25.
- 9.
- 25%: 18 ÷ 72 = 0.25.
- 50.
- $40: the reduction is $10.