View source for Division sign

{{Short description|Mathematical symbol}}
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{{About||other signs used for division|Division (mathematics)#Notation}}
{{Infobox symbol
|mark=÷
|unicode={{unichar|F7|Division sign|html=}}
|see also = {{unichar|D7|nlink=Multiplication sign}}
|different from = {{unichar|2052|nlink=Commercial minus sign|}}<br/>{{unichar|2B|Plus SIGN|nlink=Plus and minus signs}}<br>{{unichar|2020|Dagger|nlink=Dagger (mark)}}<br />{{unichar|034B|combining homothetic above|nlink=Combining Diacritical Marks}}
}}

The '''division sign''' ({{char|'''÷'''}})  is a [[Glossary of mathematical symbols|mathematical symbol]] consisting of a short horizontal line with a dot above and another dot below, used in [[Anglophone]] countries to indicate the operation of [[Division (mathematics)|division]]. This usage, though widespread in some  countries, is not universal and the symbol has a different meaning in other countries. Its use to denote division is not recommended in the [[ISO 80000-2]] standard for [[mathematical notation]].<ref name=ISO />

==In mathematics==
[[File:Skjermbilete 2012-11-03 kl. 02.48.36.png|thumb|Plus and minuses. The obelus{{snd}} or division sign{{snd}} used as a variant of the minus sign in an excerpt from an official Norwegian trading statement form called «Næringsoppgave 1» for the taxation year 2010.]]
{{further|Division (mathematics)#Notation}}

The [[obelus]], a historical [[glyph]] consisting of a horizontal line with (or without) one or more dots, was first used as a symbol for division in 1659, in the [[algebra]] book ''{{lang|de|Teutsche Algebra}}'' by [[Johann Rahn]], although previous writers had used the same symbol for subtraction.<ref name="Cajori">{{cite book |title=A history of mathematical notations |volume= 1. Notations in Elementary Mathematics |publisher=The Open Court Company |year=1928 |first=Florian |last=Cajori |author-link=Florian Cajori |pages=242, 270–271 |url=https://archive.org/details/in.ernet.dli.2015.200372/page/n261/mode/2up }}   [https://archive.org/details/in.ernet.dli.2015.200372/page/n289/mode/2up pp 270,271] </ref>  Some near-contemporaries believed that [[John Pell (mathematician)|John Pell]], who edited the book, may have been responsible for this use of the symbol.<ref name="Cajori" /> Other symbols for division include the [[slash (punctuation)|slash]] or solidus {{char|/}}, the [[colon (punctuation)|colon]] {{char|:}}, and the [[fraction (mathematics)#Vocabulary|fraction bar]] (the horizontal bar in a vertical fraction).<ref>{{Cite web|last=Weisstein|first=Eric W.|title=Division|url=https://mathworld.wolfram.com/Division.html|access-date=2020-08-26|website=mathworld.wolfram.com|language=en}}</ref><ref>{{Cite web|title=Division|url=https://www.mathsisfun.com/numbers/division.html|access-date=2020-08-26|website=www.mathsisfun.com}}</ref> The ISO 80000-2 standard for mathematical notation recommends only the solidus {{char|/}} or "fraction bar" for division, or the "colon" {{char|:}} for [[ratio]]s; it says that the {{char|÷}} sign "should not be used" for division.<ref name=ISO>ISO 80000-2, Section 9 "Operations", 2-9.6</ref>

In [[Italy]], [[Poland]] and [[Russia]], the {{char|÷}} sign was sometimes used to denote a [[Interval (mathematics)|range of values]], and in [[Scandinavia]]n countries it was, and sometimes still is, used as a negation sign:<ref>{{cite book |chapter-url=https://www.unicode.org/versions/Unicode10.0.0/ch06.pdf#G7935 | page=280, Obelus | chapter = 6. Writing Systems and Punctuation | publisher= Unicode Consortium | title = The Unicode® Standard: Version 10.0 – Core Specification | date= June 2017}}</ref> the [[Unicode Consortium]] has allocated a separate [[code point]], {{unichar|2052|commercial minus sign|nlink=}} for this usage uniquely;<ref name=Silli1>{{cite web |title=Too narrowly defined: DIVISION SIGN & COLON |url=http://www.unicode.org/mail-arch/unicode-ml/y2012-m07/0053.html | author = Leif Halvard Silli | website= Unicode.org}}</ref><ref name=Silli2>{{cite web |url=https://www.unicode.org/mail-arch/unicode-ml/y2014-m01/0018.html | title= Commercial minus as italic variant of division sign in German and Scandinavian context | author = Leif Halvard Silli | website= Unicode.org}}</ref> the exact form of the symbol displayed is typeface (font) dependent.

==In computer systems==
===Encoding===
The symbol was assigned to [[code point]] 0xF7 in [[ISO 8859-1]], as the "division sign". This encoding was transferred to [[Unicode]] as U+00F7.<ref>{{citation|title=Unicode Explained: Internationalize documents, programs, and web sites |first=Jukka |last=Korpela |publisher=O'Reilly Media, Inc. |year=2006 |isbn=9780596101213 |page=397 |url=https://books.google.com/books?id=PcWU2yxc8WkC&pg=PA397}}</ref> In [[HTML]], it can be [[Character encodings in HTML|encoded]] as {{code|&divide;}} or {{code|&#xF7;}} (at [[List of XML and HTML character entity references|HTML level]] 3.2), or as {{code|&#247;}}.

[[Unicode]] provides various division symbols:<ref>{{Cite web |title=Division symbol |url=https://divisionsymbol.net}}</ref>
{| class="wikitable"
! Code Point !! Name !! Symbol
|-
| U+00F7 || Division Sign || ÷
|-
| U+27CC || Long Division || ⟌
|-
| U+2215 || Division Slash || ∕
|-
| U+2A38 || Circled Division Sign || ⨸
|-
| U+2797 || Heavy Division Sign || ➗
|-
| U+2298 || Circled Division Slash || ⊘
|-
| U+22C7 || Division Times || ⋇
|-
| U+29BC || Circled Anticlockwise-Rotated || ⦼
|}

===Keyboard entry===
In [[Microsoft Windows]], this division sign is produced with [[Alt key|Alt]]+0247 (or 246 with no zero) on the number pad, or by pressing {{Key press|[[Alt Gr]]|Shift|+}} when an appropriate [[keyboard layout]] is in use. In [[classic Mac OS]] and [[macOS]], it is produced with {{Key press|[[Option key|⌥ Option]]|/}}.

On UNIX-based systems using [[GNU Screen|Screen]] or [[X Window System|X]] with a [[Compose key]] enabled, it can be produced by composing {{Key press|:}} (colon) and {{Key press|-}} ([[hyphen-minus|hyphen/minus]]). It may also be produced using its Unicode code-point (F7), by pressing {{Key press|Control|Shift|u}}{{nbsp}}{{keypress|f|7|space|chain=}}.

In [[LaTeX]], the division sign is obtained by the command {{code|\div}}.

In [[ChromeOS]] (with International/Extended keyboard setting), the division sign is obtained by pressing {{keypress|AltGr|shift|+}}. Otherwise, the Unix-style methods may be used.

==See also==
* [[Plus and minus signs]]
* [[Multiplication sign]]

==Notes==
{{reflist}}

==External links==
*[http://jeff560.tripod.com/operation.html Jeff Miller: ''Earliest Uses of Various Mathematical Symbols'']
*[http://www.worldwidewords.org/articles/signs.htm Michael Quinion: ''Where our arithmetic symbols come from'']
{{wiktionary-inline}}

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[[Category:Mathematical symbols]]
[[Category:Typographical symbols]]
[[Category:Division (mathematics)]]
[[Category:Ancient Greek punctuation]]