Real number
A real number is a number that falls on the real number line. It can have any value. Some examples of real numbers are:
, and so on. Numbers that are not real are 
, 
, 
, i.e. complex numbers, and quaternions.
The set of real numbers is denoted by 
. Commonly used subsets of the real numbers are irrational numbers (
), rational numbers (
), integers (
), and natural numbers (
).
