# Chapter 10. Playing with Percentages

In This Chapter

• Defining a percentage

• Checking out four frequently used conversions

• Performing basic percentage math

The words percent and percentage are everywhere. No matter your occupation, you most likely encounter percentages, both as part of your day-to-day tasks and as part of the business side, including buying things, selling things, and paying people. Percentages are also part of common talk and always make appearances in the media, which is just fine when you understand what percentages are and how to use them. But if you don't, you can end up with some big errors and distorted information.

In this chapter, you find out what a percentage is and how to convert numbers to percentages. As a bonus, you convert percentages to numbers. And you even discover some shortcuts, too.

# Pinpointing Percentages: Half a Glass Is Still 50 Percent Full

You take half, I'll take half. Isn't that the same as saying we'll split something 50/50 or saying 50 percent for you and 50 percent for me? That's three ways of saying the same thing.

To put it simply, a percentage is a way of saying how large or small a quantity is compared to another quantity. It doesn't get a bit more complicated than that. (You can also call a percentage a percent or a per cent.) For the simplest things in life, simple words like "half" work fine. The old saying asks, "Is the glass half full or half empty?" The optimist looks at how much is in the glass. The pessimist looks at how little ...

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