Enter the number
Press the percentage key (%), if your calculator has one
For x% of a number: multiply the number by x, then divide by 100
For example: 200 × 15 ÷ 100 = 30
For percentage increase: subtract the original from the new, divide by the original, then multiply by 100
For percentage decrease: subtract the new from the original, divide by the original, then multiply by 100
For finding what percent one number is of another: divide the part by the whole, then multiply by 100
For example: 25 ÷ 200 × 100 = 12.5%