 Home    |    Teacher    |    Parents    |    Glossary    |    About Us            We use the percent symbol (%) to express percent. Percents are used everywhere in real life, so you'll need to understand them well. Here are three ways to write the same thing:

15% = 15/100 = 0.15

Fifteen percent is the same as the fraction 15/100 and the decimal 0.15. They all simply mean "fifteen out of a hundred." A percent can always be written as a decimal, and a decimal can be written as a percent, like this:

0.85 = 85%

We can find any percent of a given number by changing the percent to a decimal and multiplying. One hundred percent of a number is just the number itself. Two hundred percent of a number is twice that number.

100% of 50 -> 50
200% of 50 -> 2 x 50 = 100

Let's find 30 percent of 400:

First change 30% to a decimal by moving the decimal point 2 places to the left.

30% = 0.30

Then multiply.

0.30 x 400 = 120

30% of 400 is 120.

Mental Math
There's an easy way to find 10% of a number without multiplying. Just move the decimal point in the number left by one place. Let's try it with these numbers:

895 27 10,411

10% of 895 = 89.5
10% of 27 = 2.7
10% of 10,411 = 1,041.1

Examples
Write each as a percent:

\$6 out of \$12 -> \$6/\$12 = 0.5 = 50%
34 out of 100 -> 34/100 = 0.34 = 34%
0.55 = 55%
1.2 = 120%

Find the value of n for each problem:

n is 50% of 60 -> n = 0.5 x 60 = 30
n is 4% of 33 -> n = 0.04 x 33 = 1.32
n is 150% of 24 -> n = 1.5 x 24 = 36

 Homework Help | Pre-Algebra | Numbers Email this page to a friend   Search   ·  Place value ·  Decimal numbers ·  Estimating and     rounding ·  Adding / subtracting     decimals ·  Multiplying decimals ·  Dividing decimals ·  Percent ·  Exponents ·  Square roots ·  Signed integers ·  Adding and     subtracting integers ·  Multiplying and     dividing integers ·  Properties of integers          First Glance In Depth Examples Workout Percent