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Converting Whole Numbers
and Decimals to Percents

by Gail Englert

A response to the question:

What is the simplest way to teach a student how to convert whole numbers and decimals into percents?

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I need the simplest way to teach a student how to convert whole numbers and decimals into percents.

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I noticed you referenced the middle grades when you asked your question. You asked for the easiest way...

Here is what I would do with students in grades 6 - 8 who needed help understanding how to convert whole numbers and decimals into percents.

I would explain that the percent sign is a "shorthand" way of saying "out of (each) 100" or "per hundred", so 20 percent means 20 out of each 100, and 85 percent means 85 out of each hundred.

If you know that, you can switch it around to ask "what percent"

.14 is 14% because .14 means 14 out of 100 already when you write it as a fraction.

1.4 (which is the same as 1.40) means 1 and 4/10 , or 1 and 40/100 -- or 140/100 ... so 1.4 = 140%.

14 can also be written as a fraction 14/1, or 140/10, or 1400/100, so 14 is 1400%.

Ask your students if they see a pattern.

          .14  =                            14/100   =    14%
         1.4   =             14/10   or    140/100   =   140%
        14     = 14/1   or  140/10   or   1400/100   =  1400%

What is happening to the whole number or decimal number on the left when you change it to a fraction, and then to a percent?

Will this work each time? Encourage your students to try it again with another set of numbers, and use a calculator to check and see if the percents they come up with are correct.

I am hoping you will try this way, even though it may require a bit more effort. In the long run, if a student understands what he/she is doing, it is easier to build on the understanding.

-Gail, for the T2T service

Join a discussion of this topic in T2T.

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