## Key Concepts

**Real numbers**

### The Order of Operations

- Perform all operations within grouping symbols first. Grouping symbols include parentheses ( ), brackets [ ], braces { }, and fraction bars.
- Evaluate exponents or square roots.
- Multiply or divide, from left to right.
- Add or subtract, from left to right.

This order of operations is true for all real numbers.

## Glossary:

**Irrational number**- A number that cannot be written as the ratio of two integers. Its decimal form does not stop and does not repeat.

**Rational number**- A number that can be written in the form [latex]{\Large\frac{p}{q}}[/latex] , where
*p*and*q*are integers and [latex]q\ne 0[/latex] . Its decimal form stops or repeats.

**Real number:**- A number that is either rational or irrational.