Writing Percents as Decimals

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Writing Percents as Decimals

Unit 4 > Lesson 4 of 9

Problem:	What is 35 percent of one dollar?

	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:

Remove the percent symbol.
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% =

From your knowledge of decimal place value, you know that = 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%		.18
07%		.07
82%		.82
55%		.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: