# The Real Number System

Rational numbers

Integers

Whole numbers

 Natural numbers

Irrational
numbers

The set of real numbers consists of the set of rational numbers and the set of irrational numbers. The set of rational numbers has several subsets of numbers: the natural numbers, the whole numbers, the integers and the rationals.
Overview of the Real Number System

NATURAL NUMBERS
The set of natural numbers are the counting numbers
(1, 2, 3, ...…) and is the first set of numbers that children learn. The set of natural numbers is denoted .

Even & odd numbers

WHOLE NUMBERS
The set of whole numbers contains the set of natural numbers and the number zero.
Zero snack activity        Whole number movie

INTEGERS
The set of integers contains the set of whole numbers and their negatives ( ..., -2, -1, 0, 1, 2, 3, ... ). The set of integers is denoted Z .

RATIONAL NUMBERS
The set of rational numbers contains all the possible ratios of two integers a/b where b is not zero. The set of rational numbers is denoted .
Rational numbers

IRRATIONAL NUMBERS
The set of irrational numbers contains all the numbers which are not rational numbers. The most famous examples are and e. Note that all real numbers are either rational or irrational.
Irrational numbers