Ancient roots
The most primitive method of representing a natural number is to use one's fingers, as in finger counting. Putting down a tally mark for each object is another primitive method. Later, a … See more

There are two standard methods for formally defining natural numbers. The first one, named for Giuseppe Peano, consists of an autonomous See more

• "Natural number", Encyclopedia of Mathematics, EMS Press, 2001 [1994]
• "Axioms and construction of natural numbers". apronus.com. See more

This section uses the convention $${\displaystyle \mathbb {N} =\mathbb {N} _{0}=\mathbb {N} ^{*}\cup \{0\}}$$.
Addition
Given the set See more

Two important generalizations of natural numbers arise from the two uses of counting and ordering: cardinal numbers and See more

• Bluman, Allan (2010). Pre-Algebra DeMYSTiFieD (Second ed.). McGraw-Hill Professional. ISBN 978-0-07-174251-1 – via Google Books. See more