#computer-arithmetic ## Definition > [!tldr] Definition > An **integer** is a whole number. That is, an integer is any number from the list $\dots, -2, -1, 0, 1, 2, \dots$. The set of all integers is denoted $\mathbb{Z}$. Integers form the building blocks of mathematics and are the central organizing tool for computer mathematics particularly. The [[natural numbers]] are a [[subset]] of the integers, namely the nonnegative integers $0, 1, 2, 3, \dots$. ## Examples and Non-Examples Some examples of integers include $10$, $99999$, $-20$, and $0$. Some non-integers include: - $1/2$ (not a whole number) - $\sqrt{5}$ (also not a whole number) - $2 + 3i$ (not a real number) - $\infty$ (not a number at all) ## Resources - [Mathworld article on integers](https://mathworld.wolfram.com/Integer.html) - [Math is Fun article on integers, with practice exercise](https://www.mathsisfun.com/definitions/integer.html)