Percentages


  1. Fraction to percentage: Multiply fraction by 100 and put % sign.

  2. Percentage to Fraction: Divide percentage by 100, reduce fraction to simplest form and remove % sign.

  3. Decimal to percentage: Move decimal point 2 places to the right and add % sign.

  4. Percentage to Decimal: Move decimal point 2 places to the left and remove % sign.

  5. Fraction-Percentage values to remember:
           1
    2
      =  50 %,
            1
    3
      =  33.33 %,
           1
    4
      =  25 %,

           1
    5
      =  20 %,
            1
    6
      =  16.66 %,
           1
    7
      =  14.28 %,

           1
    8
      =  12.25 %,
       1
    9
      =  11.11 %,
           1
    10
      =  10 %,

           1
    11
      =  9.09 %,
       1
    12
      =  8.33 %,
           1
    13
      =  7.69 %,

           1
    14
      =  7.14 %,
       1
    15
      =  6.66 %,
           1
    16
      =  6.25 %,

           1
    17
      =  5.88 %,
       1
    18
      =  5.55 %,
           1
    19
      =  5.25 %,

           1
    20
      =  5 %,
             1
    25
      =  4 %,
                1
    50
      =  2 %,

    Examples:
    1. 6.25 % of 320 =
       320
    16
      =  20

    2. 20 % of 630 =
       630
    5
      =  126

  6. Quantity X as percentage of quantity Y =
       X
    Y
     × 100

  7. What percentage of a is b =
       b
    a
     × 100

  8. Percentage increase or decrease in a quantity =
       Actual increase/decrease
    Original quantity
     × 100

  9. What percentage is X more than Y =
       (X - Y)
    Y
     × 100

  10. What percentage is X less than Y =
       (Y - X)
    Y
     × 100