This document defines and provides examples of different types of real numbers including natural numbers, whole numbers, integers, rational numbers, and irrational numbers. Natural numbers are counting numbers like 1, 2, 3. Whole numbers include 0. Integers include both positive and negative numbers. Rational numbers are fractions or decimals that can be written as a ratio of two integers. Irrational numbers are non-repeating, non-terminating decimals. The real number system includes all rational and irrational numbers.