


Percents
A percent is another way to describe a part
of a whole (which means that percents are also another way to talk
about fractions or decimals). Percent literally means “of 100” in
Latin, so when you attend school 25 percent of the time, that means
you only go to school ^{25}/
_{100} of the time (or .25).
You would probably fail all your classes if your attendance
percentage was that low, so don’t get any ideas from our example.
Instead, take a look at this question: 3 is what percent of 15?
This question presents you with a whole, 15, and then
asks you to determine how much of that whole 3 represents in percentage
form. Since a percent is “of 100,” to solve the question you have
to set the fraction ^{3}/
_{15} equal to ^{x}⁄_{100}:
You then crossmultiply and solve for x:
Converting Percents into Fractions or Decimals
You should be skilled at converting percents into fractions
and decimals, because these problems will definitely come up on
the Math IC test.
Percents relate to decimal numbers very simply and directly.
A percent is a decimal number with the decimal point moved two decimal
places to the left.
For example:
To convert from a decimal number to a percent, move the
decimal point two places to the right:
On an even more simplistic level, we can just say that
50% = .5 or 22.346% = .22346. Percentages greater than 100 exist,
too. 235% = 2.35, for example.
To convert from a percent to a fraction, take the percentage
number and place it as the numerator over the denominator 100. 58
percent is the same as ^{58}/
_{100} .
To convert from a fraction back to a percent, the easiest
method is to convert the fraction into a decimal first and then
change the resultant decimal into a percent.
