Percents and Decimals

The word percent means “hundredths” or “divided by 100.”  The symbol % is used to represent percent.

            39% means 39 divided by 100 or

To convert a percentage to a decimal, remove the percent sign and divide by 100.  (You can achieve the same result by moving the decimal point two places to the left.)

            16.2% = 0.162

              25 % = 0.25

To convert a decimal to a percentage, multiply by 100 and add the decimal point.  (You can achieve the same result by moving the decimal point two places to the right.)

            0.065 = 6.5%

              3.75 = 375%

To find a percentage of a number, multiply the number by the decimal equivalent of the percent.

Example 1:

What is 30% of 40?

(0.30)(40) = 12

12 is 30% of 40.

To find what percent one number is of another, divide and convert the answer to the equivalent percent.

Example 2:

3 is what percent of 4?

3 ÷ 4 = 0.75 = 75%

3 is 75% of 4.

To find a number that is a certain percentage of another number, divide the number by the decimal equivalent of the percentage.

Example 3:

3 is 15% of what number?

3 ÷ 0.15 = 20

3 is 15% of 20.

To change a fraction into a percentage, divide to find its decimal equivalent and then change the decimal to the percentage.

            15/20 = 0.75 = 75%