The Natural Numbers
The natural numbers are the counting numbers. They are the numbers 1, 2, 3, 4, 5, and so forth.
Some textbooks disagree and say the natural numbers include 0, also, and use the term counting numbers for the set {1, 2, 3, 4, 5, ...}.
The set of natural numbers is a subsets of the integers, but does not include the negative integers (or, usually, 0).
The Venn diagrams below shows the relationships of the various sets of numbers.
