Decimals are also parts of 100, but they are expressed as "points" rather than "percent." Think of taking a child's temperature: 98.6—"ninety-eight point six"—is really 98 and six-tenths (a fraction—we'll get to those in a moment) or 98 and 60 percent.
Real Life, Real Money Use
To use decimals in real life, you need to be able to convert decimals to percentages. When you shop the sales, for instance, you'll see signs (particularly after the holidays) that say items are selling for 40%-off the original price. Suppose the original price of an item is $120. How can you find out how much 40 percent of $120 is?
- First, convert 40 percent into a decimal. To do that, start at the right-hand side of the number and put a period two digits to the left.
40% becomes the decimal .40
(7% would become the decimal .07)
- Then multiply the decimal by the original price to get the discount.
$120 x .40 = $48)
- Finally, subtract the discount from the original price to get the new selling price.
$120 – $48 = $72.
Math 101 continues...