Key Concepts

• Opposite Notation
  • $-a$ means the opposite of the number $a$
  • The notation $-a$ is read the opposite of $a$.
• Absolute Value Notation
  • The absolute value of a number $n$ is written as $|n|$ .
  • $|n|\ge 0$ for all numbers.

Glossary

absolute value

The absolute value of a number is its distance from 0 on the number line.

integers

Integers are counting numbers, their opposites, and zero … $–3, –2, –1, 0, 1, 2, 3\dots$

negative number

A negative number is less than zero.

opposites

The opposite of a number is the number that is the same distance from zero on the number line, but on the opposite side of zero.