Natural Numbers:
(the counting numbers)
1, 2, 3, ....
Whole Numbers:
0, 1, 2, 3.... (the natural numbers and zero)
Integers:
...-3, -2, -1, 0, 1, 2, 3, ....
the natural numbers, whole numbers and negative whole numbers
Rational Numbers:
A number that can be expressed as a fraction or ratio
e.g. 1/4, 1.5
Irrational Numbers:
cannot be written as a simple fraction
e.g. 3.1415926535897932384626433832795..... (pi)
