Idiot\'s Guides Basic Math and Pre-Algebra

90 Part 1: The World of Numbers

Let’s walk through some examples of the different types of problems. First, finding a percentage.

What percentage of 58 is 22?

Look for “of.” 58 is the whole. Look for “is.” 22 is the part.

22 is about 37.9 percent of 58.

You might round an answer like that to 38 percent if you don’t want to deal with the decimal.

It will depend on the work you’re doing. If you were going to compare two percentages that

were both close to 38 percent, you’d want the decimals so you could see which was bigger. If you

want to know how much your savings increased, 38 percent is probably just as informative as

37.9 percent.

Let’s look at another example. In this one, you’ll find the whole.

46 is 27% of what number?

Look for “of.” The whole is “what number,” which means it is unknown. Look for “is.” 46 is the

part. Both 46 and 27 are near the “is” but 27 has the % sign, so you know it is the percentage.

46 is 27% of 170.4, approximately. Again, how much you round will depend on the situation.

part

whole

%

100

22

58 100

58 2200

37.9

x

x

x







part

whole

%

100

46 27

100

27 4600

170.4

x

x

x