Real numbers

A real number is any number we can think of; real numbers include whole numbers (0, 1, 2, 3), rational numbers (2/6, 0.768, 0.222..., 3.4), and irrational numbers (π, √3). Real numbers can be positive, negative, or zero. Imaginary numbers, on the other hand, are like √?1 (the square root of minus 1); note that infinity is not a real number.