Jump to content

Arithmetic/Percents Decimals and Fractions

From Wikibooks, open books for an open world

Conversions between percents, decimals and fractions

[edit | edit source]

The perhaps easiest way to convert from:

Decimal to fractions is by simply moving the period over 2 and putting it over a 100

(ex) Express .50 as a fraction

   .500   = 50.0 = 50/100 = 1/2
   . >. (this means the moving of the dot)

usually the best way to set it all up is the following

                             ------------------------------
                            | fraction | Decimal | percent |
                            |    ?     |   ?     |   50%   |
                              ------------------------------
           (move 2 to the right)    <--   x       -->(move dot over 2 to the right)  
              (and put over 100)
When converting decimal to fraction                  When converting from decimal to percent
always be sure it has 2 place to the                 this always works   
right of the (.)                                     ? = 50.% if its not known, do the "reverse"
(ex)   .5 = .50   = ? =  50                         .50 <--.
            .-->   ---  ---
                   100  100

When reading decimals, it is similar to verbalizing a fraction. For example, 0.2 is spelled out as "two-tenths", hence 2/10, which simplifies to 1/5. What if you had the real number 0.002? Same principle: "two-thousandths" implies 2/1000, which reduces to 1/500.

Previous: Grammar
Next: Simple symbolic manipulation
Return to: Algebra Outline

华夏公益教科书