Chapter 1
Linear Equations and Graphing
Course: Gre
Subject: Gre Quantitative Reasoning
Chapter: Linear Equations And Graphing
What is Absolute Value?
Absolute value is the distance of a number from 0 on a number line. Because distance is always positive or zero, absolute value is always nonnegative.
Key Idea: Direction Doesn't Matter
Think of walking from your home to school and back. The distance traveled is the same in both directions—only the distance matters, not which way you're going. Absolute value works the same way: it only cares about how far a number is from zero, not whether it's positive or negative.
Examples:
- |2| = 2 and |−2| = 2 (both are 2 units from 0)
- |5| = 5 and |−5| = 5
- |0| = 0
Terminology:
- Modulus is another word for absolute value
- |x| means "the absolute value of x" or "modulus x"
- A variable is a symbol (like x, y, n) used to stand for a number