Chapter 3

# Getting Down with Negative Numbers

In This Chapter

Understanding negative numbers

Finding the absolute value of a number

Adding and subtracting negative numbers

Multiplying and dividing negative numbers

*Negative numbers,* which are commonly used to represent debt and really cold temperatures, represent amounts less than zero. Such numbers arise when you subtract a large number from a smaller one. In this chapter, you apply the Big Four operations (adding, subtracting, multiplying, and dividing) to negative numbers.

## Understanding Where Negative Numbers Come From

When you first discovered subtraction, you were probably told that you can't take a small number minus a greater number. For example, if you start with four marbles, you can't subtract six because you can't take away more marbles than you have. This rule is true for marbles, but in other situations, you *can* subtract a big number from a small one. For example, if you have $4 and you buy something that costs $6, you end up with less than $0 dollars — that is, –$2, which means a *debt* of $2.

A number with a minus sign ...

Get *Basic Math and Pre-Algebra Workbook For Dummies, 2nd Edition* now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.