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Writing Percents as Decimals Unit 4 > Lesson 4 of 9

Problem: What is 35 percent of one dollar?   [IMAGE]
  We know from the previous lesson that .35 = 35%. The word "of" means multiply. So we get the following:
  35% x $1.00 = .35 x $1.00
  since $1.00 = 1, we get .35 x $1.00 = .35 x 1 = .35
  35% of $1.00 is $.35
Solution: 35% of one dollar is $.35, or 35 cents.

The solution to the above problem is not surprising, since percents, dollars and cents are all based on the number 100. To convert a percent to a decimal, first remove the percent symbol, then move the decimal point two places to the left. Look at the Example 1 below.


Example 1: Write each percent as a decimal:     18%,    7%,    82%,    55%
 
Solution
Percent Decimal
18% .18
07% .07
82% .82
55% .55

In Example 1, it was easy to convert each percent to a decimal since each percent had two digits. (The exception to this was 7% for which we needed to add in a zero in order to make the conversion.) Thus, we need a procedure to follow for consistency.

To write a percent as a decimal, follow these steps:
  1. Remove the percent symbol.
  2. Move the decimal point two places to the left, adding in zeros as needed.

Why do we move the decimal point 2 places to the left?

Remember that percent means parts per hundred, so 18% = [IMAGE]

From your knowledge of decimal place value, you know that [IMAGE] = 0.18  (eighteen hundredths).

Thus, 18% must also equal 0.18.


Let's take another look at Example 1, this time including the fractional equivalents of each percent.

Example 1: Write each percent as a decimal:     18%,    7%,    82%,    55%
 
Solution
Percent Fraction Decimal
18% [IMAGE] .18
07% [IMAGE] .07
82% [IMAGE] .82
55% [IMAGE] .55

Let's look at another example of writing percents as decimals.

Example 2: Write each percent as a decimal:     12.5%,    89.19%,    39.2%,    71.935%
 
Solution
Percent Decimal
12.5%       .12500
89.19%    .89190
39.2%       .39200
71.935% .71935


Summary: To write a percent as a decimal, remove the percent symbol, then move the decimal point two places to the left, adding in zeros as needed.

Exercises

Directions: Read each question below. Select your answer by clicking on its button. Immediate feedback is provided in the RESULTS BOX. If you make a mistake, choose a different button.

1.  Which of the following is equal to 64%?

      .064
      .64
      6.74
      None of the above.

      RESULTS BOX:
          


2.  Which of the following is equal to 7.27%?

      7.27
      .727
      .0727
      None of the above.

      RESULTS BOX:
          


3.  Which of the following is equal to 91.4763%?

      .914763
      9.14673
      91.4763
      None of the above.

      RESULTS BOX:
          


4.  Which number has the greatest value?

      19.72%
      1.972
      $19.72
      20 cents

      RESULTS BOX:
          


5.  Which number has the least value?

      1.039%
      1.39
      $1.39
      139 cents

      RESULTS BOX:
          



This lesson is by Gisele Glosser. You can find me on Google.

Understanding Percent Lessons
Meaning of Percent
Writing Fractions as Percents
Writing Decimals as Percents
Writing Percents as Decimals
Writing Percents as Fractions
Percents < 1 or > 100
Practice Exercises
Challenge Exercises
Solutions

Related Activities
Percent Crossword Puzzles
Percent in Daily Life WebQuest
Percent Goodies Game
Percentage Worksheet Generator
Pre-Made Percent Worksheets

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