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Percents Basics

Percent means part of a whole.
The whole is represented by 100%
  • Changing a whole number into a percent
    a) Write 7 as a percent. Find the invisible decimal. It's behind the whole number. Move it 2 places to its right and place zeroes in the two places. Therefore 7 = 700%
    b) Write 14 as a percent. Find the invisible decimal. It's behind the whole number. Move it 3 places to its right and place zeroes in the two places. Therefore 14 = 1400 %

  • Changing a decimal to percent and back to decimal:
    a) Write .34 as a percent = 34% - as percent contains two zeros, move the decimal 2 places to the right, add the percent sign. Note the decimal point is invisible
    b) Write 0.0085 as a percent = 0.85% as percent contains two zeros, move the decimal 2 places to the right, add the percent sign after the numbers.
    c) Write 3.64 as a percent = 364% - as percent contains two zeros, move the decimal two places to where the percent sign sits and ad
    d the sign. Note the decimal point is invisible.

  • Changing a percent to a decimal:
    a) Write 45% as a decimal = .45 - as percent contains two zeros, move the decimal 2 places away from the percent or to the left - drop the percent sign and add zeros as needed.
    a) Write 70.4% as a decimal = .704 - as percent contains two zeros, move the decimal 2 places away from the percent - or to the left - drop the percent sign and add zeros as needed.

  • Change a fraction to a decimal or percent and back:
    a) Write 4/5 as a percent - first change 4/5 into a decimal- read the problem as 4 divided by 5. Write it as a division problem - there is an invisible decimal after the 4 - 5 cannot to go into 4 -
    Put in the invisible decimal and add a zero – it looks like the answer is .8
    (if you look at rule number 2) is 80%
    b) Write 75% as a fraction -first convert a decimal 0.75-that read words - seventy-five hundredths-now why to as a fraction 75 over 100 and be sure to reduce this to 3/4. HINT - count the number of places after the decimal - replace with an equal number of zeros - now place a one in front of the zero. Therefore 0.0702 = 702 over 10000 reduced = 301 over 5000.

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