Real Number System

Types of Numbers

• Natural Numbers - You count them, starting at 1
• Examples: $1,\ 2,\ 3,...$
• Whole Numbers - You count them, starting at 0
• Examples: $0,\ 1,\ 2,\ 3,...$
• Integers - Positive and negative whole numbers
• Examples: $...,\ -3,\ -2,\ -1,\ 0,\ 1,\ 2,\ 3,...$
• Rational Numbers - Any number that can be written as a quotient (dividion) $\displaystyle \frac{a}{b}$ where $a$ and $b$ are integers and $b\neq 0$
• Examples: $\displaystyle \frac{2}{5},\ -\frac{11}{3},\ 3\frac{1}{2},\ 0.5,\ -1.23,\ 3.\overline{3}$
• Irrational Numbers - Any number that cannot be written as a quotient of integers
• Examples: $\sqrt{2}$, $\pi$, $\sqrt{3}$, ...
• Real Numbers - Any number that can be written on the number line