Basic Math and Pre-Algebra For Dummies (66 page)

To solve this problem, begin by jotting down what the first sentence tells you:

Doreen ate part of what was left, so write a word equation that tells you how much of the pie was left after Jerry was finished. He started with a whole pie, so subtract his portion from 1:

Next, Doreen ate
of this amount. Rewrite the word
of
as multiplication and solve as follows. This answer tells you how much of the whole pie Doreen ate:

To make the numbers a little smaller before you go on, notice that you can reduce the fraction:

Now you know how much Jerry and Doreen both ate, so you can add these amounts together:

Solve this problem as I show you in Chapter
10
:

This fraction reduces to
. Now you know that Jerry and Doreen ate
of the pie, but the problem asks you how much is left. So finish up with some subtraction and write the answer:

The amount of pie left over was
.

In the preceding section, “Problems about Multiplying Fractions,” I show you how the word
of
in a fraction word problem usually means multiplication. This idea is also true in word problems involving decimals and percents.
The method for solving these two types of problems is similar, so I lump them together in this section.

 You can easily solve word problems involving percents by changing the percents into decimals (see Chapter
12
for details). Here are a few common percents and their decimal equivalents: