Percents, Decimals,

1
Percents, Decimals, Fractions

• Section 7.1

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Understanding Percent

• Percent means per 100
• Example 47 means 47 per 100
• This can also be stated as the
  ratio of 47 to 100
• And, therefore, can be written as
• 47/100

3
Examples of the Usage of Percent

• The interest rate is 12.5
• 68 of homes have Internet access
• The store is having a 75 off sale (so, what
  percent of the original price is being charged?)
• 34 of the class is female
• The number of new jobs has decreased by 27

4
Translating from words to percent

• Of 100 students in a club, 23 are freshmen. What
  percent of the students are freshmen?
• Twenty-nine out of one-hundred executives are in
  their forties. What percent of executives are in
  their forties?

5
Writing Percents as Decimals

• To convert a percent to a decimal, locate the
  decimal point in the percent, move it 2 places to
  the LEFT, and drop the percent sign.
• Example Write each percent as a decimal.
• a) 2.7
• b) 150
• c) .69
• d) 500

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Writing Decimals as Percents

• To write a decimal as a percent locate the
  decimal point, move it 2 places to the RIGHT, and
  add the percent sign.
• Example Write each decimal as a percent.
• a) .19
• b) 1.75
• c) .044
• d) .7

7
Writing Percents as Fractions

• To write a percent as a fraction drop the percent
  sign and multiply the number by 1/100.
• Example Write each percent as a fraction in
  simplest form.
• a) 25
• b) 2.3
• c) 150
• d) 66 2/3 e) 8

8
Writing Fractions as Percents

• To write a fraction as a percent, multiply by
  100/1
• Example Write each fraction as a percent.
• a) ½
• b) 7/40
• c) 2 1/4