Absolute value
Evaluate the absolute value of numbers and simple expressions.
Objective
Evaluate the absolute value of numbers and simple expressions.
What it means
Absolute value is the distance a number is from zero on the number line, always non-negative, written |n|.
See it
Use this model while you read. Move it around to see what the math is doing.
xx111
2x + 3 = 11 when x = 4.
Key terms
- Absolute value
- Distance from zero, written |n|.
- Distance
- A non-negative measure of separation between two points.
Rules to remember
- |n| = n when n ≥ 0.
- |n| = -n when n < 0 (which makes it positive).
- Absolute value is never negative.
Step by step
- 1Identify the signDetermine whether the number inside is positive or negative.
- 2Drop the signThe absolute value equals the number's distance from zero.
Common mistakes
- Treating |−n| as still negative.
- Applying absolute value before finishing operations inside the bars.
Tips
- Absolute value bars act like grouping symbols — simplify inside first.
- The output of |·| is always ≥ 0.