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(An abstract mathematical object)
 
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A '''number''' is an abstract [[mathematics|mathematical]] object hard to define. In mathematics, a number is formally a member of a given [[set]] (possibly an ordered set). It conveys the ideas of counting, ordering, and measurement. However, due to the expressiveness of [[positional number system]]s, the usefulness of [[geometry|geometric objects]], and the advances in different scientific fields, it can convey more properties and can be expressed in different notations.
A '''number''' is an abstract [[mathematics|mathematical]] object hard to define. In mathematics, a number is formally a member of a given [[set]] (possibly an ordered set). It conveys the ideas of counting, ordering, and measurement. However, due to the expressiveness of [[positional number system]]s, the usefulness of [[geometry|geometric objects]], and the advances in different scientific fields, it can convey more properties and can be expressed in different notations.
Numbers are used to count (e.g., there are 26 simple [[latin alphabet|latin letter]]s). Numbers can be compared (e.g., [[e (math)|e]] is lower than [[pi]] in the [[real number]] set). In many [[natural sciences]], they are used to measure (e.g., the weight of 50 lbs in [[imperial system]] is approximately equal to the mass of 22.7 kg in the [[metric system]]).

Revision as of 05:32, 5 March 2008

A number is an abstract mathematical object hard to define. In mathematics, a number is formally a member of a given set (possibly an ordered set). It conveys the ideas of counting, ordering, and measurement. However, due to the expressiveness of positional number systems, the usefulness of geometric objects, and the advances in different scientific fields, it can convey more properties and can be expressed in different notations.

Numbers are used to count (e.g., there are 26 simple latin letters). Numbers can be compared (e.g., e is lower than pi in the real number set). In many natural sciences, they are used to measure (e.g., the weight of 50 lbs in imperial system is approximately equal to the mass of 22.7 kg in the metric system).