Basic Mathematics for College Students

6.1 Percents, Decimals, and Fractions 505

b.From the graph, we see that the percent market share for the Deal or No Deal
website is 4.52%. To write this percent as a decimal, we proceed as follows.
Drop the % symbol and divide 4.52 by 100 by moving the decimal
point 2 places to the left. This requires that a placeholder zero
(shown in blue) be inserted in front of the 4.
Write a zero to the left of the decimal point.
4.52%, written as a decimal, is 0.0452.

0.0452

4.52%. 0 4 52

EXAMPLE (^7) Population
The population of the state of Oregon is
approximately of the population of the
United States. Write this percent as a decimal.
(Source:U.S. Census Bureau)
StrategyWe will write the mixed number
in decimal notation.
WHYWith in mixed-number form, we cannot apply the rule for writing a
percent as a decimal; there is no decimal point to move 2 places to the left.
SolutionTo change a percent to a decimal, we drop the percent symbol and
divide by 100 by moving the decimal point 2 places to the left. In this case, however,
there is no decimal point to move in 1 41 %. Since 1 41  1  41 , and since the decimal

1 14

1 14

1 14 %

Self Check 7

POPULATIONThe population of

the state of Ohio is approximately

of the population of the

United States. Write this percent

as a decimal. (Source:U.S. Census

Bureau)

Now TryProblem 59

3 34 %

equivalent of is 0.25, we can write in an equivalent form as 1.25%.

Write as 1.25.

Drop the % symbol and divide 1.25 by 100 by moving the decimal

point 2 places to the left. This requires that a placeholder zero

(shown in blue) be inserted in front of the 1.

Write a zero to the left of the decimal point.

1 14 %, written as a decimal, is 0.0125.

0.0125

. 0 1 25

1 1 41

1

4

%1.25%

4 1 1 41 %



EXAMPLE 8

a.Write 310% as a decimal. b.Write 0.9% as a decimal.

StrategyWe will drop the % symbol and divide each given number by 100 by
moving the decimal point two places to the left.

WHYRecall that to find the quotient of a decimal and 100, we move the decimal
point to the left the same number of places as there are zeros in 100.

Solution
a. Write the whole number 310 in decimal notation: 310 310.0.

Drop the % symbol and divide 310 by 100 by moving the decimal

point 2 places to the left.

Drop the unnecessary zeros to the right of the 1.

310%, written as a decimal, is 3.1.

b. Drop the % symbol and divide 0.9 by 100 by moving the decimal point 2
places to the left. This requires that a placeholder zero (shown in blue)
be inserted in front of the 0.
Write a zero to the left of the decimal point.
0.9%, written as a decimal, is 0.009.

0.009

0.9%. 0 0 9

3.1

3.10 0

310%310.0%

Self Check 8

a.Write 600% as a decimal.

b.Write 0.8% as a decimal.

Now TryProblems 63 and 67