A Positive Integer: 1, 2, 3, 4, ... (Sloane's A000027), also called a Natural Number. However, 0 is sometimes also included in the list of counting numbers. Due to lack of standard terminology, the following terms are recommended in preference to ``counting number,'' ``Natural Number,'' and ``Whole Number.''

Set | Name | Symbol |

..., , , 0, 1, 2, ... | integers | Z |

1, 2, 3, 4, ... | positive integers | Z+ |

0, 1, 2, 3, 4 ... | nonnegative integers | Z* |

, , , , ... | negative integers | Z- |

**References**

Sloane, N. J. A. Sequence
A000027/M0472
in ``An On-Line Version of the Encyclopedia of Integer Sequences.''
http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.
*The Encyclopedia of Integer Sequences.* San Diego: Academic Press, 1995.

© 1996-9

1999-05-25