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Chapter 5

Note: |

The absolute value of a number refers to its "distance" from a standard zero point. This concept is most simply explained in terms of points along an x-axis, where 0 is located at the origin, all points to the right of the origin are positive, and all points to the left of the origin are negative.

The value 5 intervals to the *right* of the origin (or zero) is +5. The value 5 intervals to the *left* of the origin is -5. However, the *distance* of each of these two values from the origin is the same: 5. "5" is the **absolute value** of both *+5* and *-5*.

Mathematically, "absolute value" has a more formal definition. Say x is a real number. Then the absolute value of x is defined as follows:

For x ≥ 0, |x| = x;

For x < 0, |x| = -x

where the vertical bars around "x" denote "absolute value of."