There are many different numbering schemes for assigning nominal numbers to entities. These generally require an agreed set of rules, or a central coordinator. The schemes can be considered to be examples of a primary key of a database management system table, whose table definitions require a database design.
In computability theory, the simplest numbering scheme is the assignment of to a set of objects such as functions, , graphs, or words in some formal language. A numbering can be used to transfer the idea of computability
A simple extension is to assign to physical objects according to the choice of some base of reference and of measurement units for counting or measuring these objects within a given precision. In such case, numbering is a kind of classification, i.e. assigning a numeric property to each object of the set to subdivide this set into related subsets forming a partition of the initial set, possibly infinite and not enumeratable using a single natural number for each class of the partition.
In some cases (such as computing, time-telling, and in some countries the numbering of floors in buildings) zero-based numbering is used, where the first entity is assigned "zero" instead of "one".
Other numbering schemes are listed by field below.
Chemistry
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CAS Registry Numbers for chemical compounds
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EC numbers for identifying
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for (classes of) hazardous substances
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for
Communications
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The E.164 numbering plan for telephone numbers, including:
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Telephone country codes
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North American Numbering Plan
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Numbering plans by country
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The IP address allocation scheme (IANA)
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The DNIC prefixes of X.25 NUAs (Network User Address) assigned by the ITU
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Object identifiers (OID)
Computing
Products
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The GS1 numbering scheme, including
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GTIN for products, which includes the UPC and EAN-13
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ISBN codes for books
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ISSN codes for periodicals
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Vehicle identification number
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Stock keeping unit (SKU)
People
Identification numbers
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National identification numbers
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Personal Numeric Code (Romania)
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Personal identification number (Denmark)
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Social Security number (United States)
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Social insurance number (Canada)
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INSEE number (France)
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National Insurance number (United Kingdom)
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Aadhaar (India)
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Personal Public Service Number (Republic of Ireland)
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Tax file number (Australia)
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Unique Master Citizen Number (former Yugoslavia)
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Det Centrale Personregister (Denmark)
Ordinals for names
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Princes of Reuss
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Popes' ordinals
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Generational ordinal suffix to names
Topics
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Dewey Decimal Classification and Universal Decimal Classification for books
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West American Digest System legal topic numbering scheme
Geography and transport
Vehicles
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Vehicle registration plates
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British Carriage and Wagon Numbering and Classification
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British Rail locomotive and multiple unit numbering and classification
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UIC classification of goods wagons
Roads
Road numbering schemes
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Arlington County, Virginia, street-naming system
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China road numbering
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Great Britain road numbering scheme
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European route by UNECE
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Numbered highways in the United States
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Edmonton, Alberta#Street layout
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Montreal
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Highways in Australia#Route numbering systems
Others/general
See also
