Natural number
This is an old revision of this page, as edited by BrianCo (talk | contribs) at 17:27, July 14, 2007. It may differ significantly from current revision.
According to most modern mathematics and logic textbooks a natural number is a non-negative integer such as 0, 1, 2, 3,... etc . Older books sometimes exclude zero, as there is a long history of people thinking that zero is unnatural or not really a number.