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## Numbersimple:Number
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Numbers should be distinguished from People like to assign numbers to objects in order to have unique names. There are various numbering schemes for doing so.
## ExtensionsNewer developments are the hyperreal numbers and the surreal numbers which extend the real numbers by adding infinitesimal and infinitely large numbers. While (most) real numbers have infinitely long expansions to the right of the decimal point, one can also try to allow for infinitely long expansions to the left, leading to the p-adic numbers. For dealing with infinite collections, the natural numbers have been generalized to the ordinal numbers and to the cardinal numbers. The former give the ordering of the collection, the latter its size. (For the finite case, the ordinal and cardinal numbers are equivalent; they diverge in the infinite case.)The arithmetical operations of numbers, such as addition, subtraction, multiplication and division, are generalized in the branch of mathematics called abstract algebra; one obtains the groupss, ringss and fields. ## Particular numbersSee: List of numbers, mathematical constants, even and odd numbers, negative and non-negative numbers, small numbers, large numbers, orders of magnitude (numbers), prime numbers## See also## External links | |||||||

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