To find a percentage of a number, enter the number, multiply by the percentage, then divide by 100
Example: 20% of 50 = 50 × 20 ÷ 100
To find what percent one number is of another, enter the part, divide by the whole, then multiply by 100
Example: 15 is what percent of 60 = 15 ÷ 60 × 100
To increase a number by a percentage, enter the number, multiply by 100 plus the percentage, then divide by 100
Example: 80 increased by 25% = 80 × 125 ÷ 100
To decrease a number by a percentage, enter the number, multiply by 100 minus the percentage, then divide by 100
Example: 80 decreased by 25% = 80 × 75 ÷ 100
On many calculators, use the percent key by entering the number, pressing the percent key, then completing the calculation
If the percent key does not work as expected, use ÷ 100 instead