MAT 040: Basic Math Learning Unit 10: Handout
Percent Notation
Meaning of percent The word percent means hundredths.
The symbol for percent is %.
A percent can be written as a fraction or a decimal.
Convert a percent to a decimal To convert a percent to a decimal, divide by 100.
A short way to divide by 100 is to move the decimal point two places to the left.
1. Drop the % sign.
2. Move the decimal point two places to the left.
Remember: The decimal point in a whole number is on the right of the number.
Consider the whole number nine. 9 = 9.
To move the point two places to the left, place a zero on the left of nine. You will get .09 if you move the point two places to the left.
Percent to Decimal Examples Example 1 Convert 5% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 5% = .05
Answer: .05 or 0.05
Example 2 Convert 20% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 20% = .20
Answer: .20 or 0.20 or .2 or 0.2
Example 3 Convert 100% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 100% = 1.00
Answer: 1.00 or 1
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Example 4 Convert 200% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 200% = 2.00
Answer: 2.00 or 2
Example 5 Convert 350% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 350% = 3.50
Answer: 3.50 or 3.5
Example 6 Convert 0.7% to a decimal. Drop the percent sign. Move the decimal point two places to the left. 0.7% = .007
Answer: .007 or 0.007
Example 7 Change to a decimal.
Change the fraction to a decimal.
Drop the % sign. Move the decimal point two places to the left.
Answer: .005 or 0.005
Example 8 Change to a decimal.
Change the fraction to a decimal.
Drop the % sign. Move the decimal point two places to the left.
Answer: .0725 or 0.0725
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Example 9 Change to a decimal.
Change the fraction to a decimal.
Drop the percent sign. Move the decimal point two places to the left.
Answer: or
Example 10 Change to a decimal.
Change the fraction to a decimal.
Drop the percent sign. Move the decimal point two places to the left.
Answer: or
Convert a decimal to a percent To convert a decimal to a percent multiply by 100.
A short way to multiply by 100 is to move the decimal point two places to the right.
1. Move the decimal point two places to the right.
2. Attach the % sign.
Decimal to Percent Examples
Example 11 Change 0.56 to a percent. Move the decimal point two places to the right. Attach the percent sign. 0.56 = 56%
Answer: 56%
Example 12 Change 1.4 to a percent. Move the decimal point two places to the right. Attach the percent sign. 1.4 = 1.40 = 140%
Answer: 140%
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Example 13 Convert 3 to a percent. Move the decimal point two places to the right. Attach the percent sign. 3 = 3.00 = 300%
Answer: 300%
Example 14 Convert 0.457 to a percent. Move the decimal point two places to the right. Attach the percent sign. 0.457 = 45.7%
Answer: 45.7%
Convert a percent to a fraction 1. If the number is a whole number, place it over 100.
2. If the number is a fraction, multiply by 1/100.
Percent to Fraction Examples
Example 15 Change 20% to a fraction. Since the number is a whole number, place it over 100. Reduce the fraction if possible.
Answer:
Example 16 Change 3% to a fraction. If the number is a whole number, place it over 100.
Answer:
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Example 17 Change to a fraction. Since the number is a mixed number, change it to an improper fraction and multiply by 1/100. The percent symbol % =
Answer:
Example 18 Change to a fraction. Since the number is a fraction, multiply by 1/100.
The percent symbol % =
Answer:
Example 19 Change 5.2% to a fraction. Place 5.2 over 100 and eliminate the decimal.
Eliminate the decimal in the numerator.
Since there is one decimal place, multiply by 10 in the numerator and denominator.
Reduce the fraction.
Answer:
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Change a fraction to a percent 1. Divide the numerator by the denominator to change the fraction to a decimal.
2. Move the decimal point two places to the right.
3. Attach the % sign.
Fraction to Percent Examples
Example 20 Change to a percent. Change the fraction to a decimal.
Move the decimal point two places to the right. Attach the % sign.
Answer: 87.5%
Example 21 Change to a percent and write the remainder as a fraction.
Divide to change the fraction to a decimal.
Carry the decimal out two places. Write the remainder as a fraction.
Move the decimal point two places to the right Attach the % sign.
Answer:
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Example 22 Change to a percent. First change the fraction to a decimal. Round the answer to the hundredths place.
It is a repeating decimal. Move the decimal point two places to the right.
Attach the % sign.
Round the answer to the hundredths place.
Answer:
Example 23 Change to a percent and write the remainder as a fraction.
Divide and change the fraction to a decimal.
Carry the decimal out two places. Write the remainder as a fraction.
1
Move the decimal point two places to the right. Attach the % sign.
Answer:
Example 24 Change to a percent. First change the fraction to a decimal. Round the answer to the hundredths place.
It is a repeating decimal. Move the decimal point two places to the right.
Attach the % sign.
Round the answer to the hundredths place.
Answer:
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Example 25 Change to a percent and write the remainder as a fraction.
Divide and change the fraction to a decimal.
Carry the decimal out two places. Write the remainder as a fraction.
Move the decimal point two places to the right. Attach the % sign.
Answer:
Example 26 Change to a percent. First change the fraction to a decimal. Round the answer to the hundredths place.
It is a repeating decimal. Move the decimal point two places to the right.
Attach the % sign.
Round the answer to the hundredths place.
Answer:
Example 27 Change to a percent and write the remainder as a fraction.
Divide and change the fraction to a decimal.
Carry the decimal out two places. Write the remainder as a fraction.
Move the decimal point two places to the right.
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Answer:
Example 28 Change to a percent and Round your answer to the hundredths place.
It is a repeating decimal. Move the decimal point two places to the right.
Attach the % sign.
Answer: Round the answer to the hundredths place.
Percents to Memorize or
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© Brenda Moore and Indian Hills Community College
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