Convert the percent to a decimal by dividing by 100
Multiply the decimal by the number you want the percent of
Example: 20% of 50 = 0.20 × 50 = 10
To find what percent one number is of another, divide the part by the whole
Multiply the result by 100
Example: 10 ÷ 50 = 0.2, then 0.2 × 100 = 20%
To increase a number by a percent, multiply by 1 plus the decimal form of the percent
Example: 50 increased by 20% = 50 × 1.20 = 60
To decrease a number by a percent, multiply by 1 minus the decimal form of the percent
Example: 50 decreased by 20% = 50 × 0.80 = 40