Percents

Percents are used to describe a part of something. Percents are used to figure out sales or the amount of interest someone will pay on a loan. When converting a percent to its fraction form, it will always have a denominator of 100.

Changing Decimals to Percents or Percents to Decimals

The important key is where to move the decimal point. If changing from decimal to a percent , you would need to move the decimal point two places to the right and add the percent sign.

Example:

0.35 = 35%

0.8 = 80%

To change from percent to decimal, need to move the decimal point two places to the left and drop the percent sign.

Example:

30% = .3

0.9% = .009

Converting Fraction to Percent Form

Divide the bottom number of the fraction into the top number and move the point two places to the right.

Example:

-or-

Multiply the fraction by 100%

Example:

Percent to Fraction

Example: 85%

Write the percent as a fraction with 100 as the denominator. Then reduce the fraction to lowest terms.

Percent of a Number

1) What is 25% of $6,500.	2) Change the percent to a fraction
n = 25% × $6,500 n = .25 x 6500 n = $1,625

Finding What Percent One Number Is of Another

There are key words to remember that will help you solve the problem it is asking you. The word ‘of’ in the sentence means to multiply. The word ‘is‘ means it is equal to.

Example: 9 is what percent of 45 The variable ‘a’ is being multiplied by 45. Need to divide by 45. 9 = a (x) 45 9 = 45a

The variable ‘a’ is being multiplied by 45. Need to divide by 45.

Therefore, 20% of 45 is 9.

Finding a Number When a Percent of It is Given

Example: 20% of what number is 16?

Change the percent to fraction form.

Need to multiply both sides of the equation by 5.