# End of textbook section. You should now be prepared to do assignment 1.1

## 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.