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6.2

Percents, Decimals, and Fractions

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 22

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The word percent comes from the Latin phrase The word percent comes from the Latin phrase per centumper centum, which means “per 100.”, which means “per 100.”

Percent means per one hundred. The “Percent means per one hundred. The “%%” symbol ” symbol is used to denote percent.is used to denote percent.

Understanding Percent

1

1% 0.01100

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 33

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0.65 0.65(100%) 65.% or 65%

Writing a Decimal as a Percent

Multiply by 1 in the form of 100%.Multiply by 1 in the form of 100%.

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 44

Copyright © 2011 Pearson Education, Inc.  Publishing as Prentice Hall.

Writing a Percent as a Decimal

43% 43(0.01) 0.43

100% 100(0.01) 1.00 or 1

Replace the percent symbol with its decimal Replace the percent symbol with its decimal equivalent, equivalent, 0.01; then multiply.; then multiply.

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 55

Copyright © 2011 Pearson Education, Inc.  Publishing as Prentice Hall.

Writing a Percent as a Fraction

43% 431 43

100 100

Replace the percent symbol with its fraction

equivalent, ; then multiply. Don’t forget to

simplify the fraction, if possible.

1

100

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 66

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Writing a Fraction as a Percent

•3 3

5 5 100% •

3 100%

5 1300

%5

60%

Multiply by 1 in the form of 100%.

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 77

Copyright © 2011 Pearson Education, Inc.  Publishing as Prentice Hall.

We know that

100% = 1

Recall that when we multiply a number by 1, we are not changing the value of that number.

Therefore, when we multiply a number by 100%, we are not changing its value but rather writing the number as an equivalent percent.

Helpful Hint

Martin-Gay, Prealgebra & Introductory Algebra, 3ed 88

Copyright © 2011 Pearson Education, Inc.  Publishing as Prentice Hall.

• To write a percent as a fraction, replace the % , replace the % symbol with its fraction equivalent, ; then symbol with its fraction equivalent, ; then multiply.multiply.

1

100

Summary of Converting Percents, Decimals and Fractions

• To write a percent as a decimal, replace the % symbol with its decimal equivalent, 0.01; then multiply.

• To write a decimal or fraction as a percent, multiply by 100%.