Natural numbers

Natural numbers are positive integers, starting from 1 (not 0). They’re used for counting discrete objects.

However, in computer science, natural numbers often include 0 as well.

In short, they are the set of numbers used for counting and ordering.

Notation

The set of natural numbers is usually denoted by the symbol \mathbb{N}:

Contained values

\mathbb{N} = \{0, 1, 2, 3, 4, 5, \ldots\}

or:

\mathbb{N} = \{1, 2, 3, 4, 5, \ldots\}

(0 may or may not be included, depending on the context.)