# Real number

Updated: 06/16/2017 by Computer Hope

In mathematics, a **real number** is almost any number, such as 2, 5, π -4, 32.3, and so on. The only numbers that are not real are imaginary numbers, which are numbers that give a negative result when squared. Real numbers can cause issues when programming, since an infinite set of numbers must fit into a finite number of bits. Since only so much room exists, rounding takes place to give certain numbers a finite, floating-point representation.