Chapter 3

Getting Down with Negative Numbers

In This Chapter

arrow Understanding negative numbers

arrow Finding the absolute value of a number

arrow Adding and subtracting negative numbers

arrow 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 ...

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