Division sign
The division sign (÷) is a symbol consisting of a short horizontal line with a dot above and another dot below, used in Anglophone countries to indicate mathematical division. However, this usage, though widespread in some countries, is not universal; it is used for other purposes in other countries and its use to denote division is not recommended in the ISO 80000-2 standard for mathematical notation.[1]
| ÷ | |
|---|---|
Division sign | |
| In Unicode | U+00F7 ÷ DIVISION SIGN (÷, ÷) |
| Different from | |
| Different from | U+2052 ⁒ COMMERCIAL MINUS SIGN U+002B + PLUS SIGN U+2020 † DAGGER U+034B ͋ COMBINING HOMOTHETIC ABOVE |
| Related | |
| See also | U+00D7 × MULTIPLICATION SIGN |
In mathematics
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 Teutsche Algebra by Johann Rahn, although previous writers had used the same symbol for subtraction.[2] Some near-contemporaries believed that John Pell, who edited the book, may have been responsible for this use of the symbol.[2] Other symbols for division include the slash or solidus /, the colon :, and the fraction bar (the horizontal bar in a vertical fraction).[3][4] The ISO 80000-2 standard for mathematical notation recommends only the solidus / or "fraction bar" for division, or the "colon" : for ratios; it says that the ÷ sign "should not be used" for division.[1]
In Italy, Poland and Russia, the ÷ sign was sometimes used to denote a range of values, and in Scandinavian countries it was used as a negation sign.[5]
Historically, an oblique form of the obelus, ⁒ (commercial minus sign), has also been used to represent subtraction in Northern Europe; such usage continued in some parts of Europe, including Norway and—until fairly recently—Denmark.
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.[6] In HTML, it can be encoded as ÷ or ÷ (at HTML level 3.2), or as ÷.
Keyboard entry
In Microsoft Windows, this division sign is produced with Alt+0247 (or 246 with no zero) on the number pad, or by pressing Alt Gr+⇧ Shift++ when an appropriate keyboard layout is in use. In classic Mac OS and macOS, it is produced with ⌥ Option+/.
On UNIX-based systems using Screen or X with a Compose key enabled, it can be produced by composing : (colon) and - (hyphen/minus). It may also be produced using its Unicode code-point (F7), by pressing Control+⇧ Shift+u f7space.
In LaTeX, the division sign is obtained by the command \div.
In ChromeOS (with International/Extended keyboard setting), the division sign is obtained by pressing AltGr+⇧ Shift++. Otherwise, the Unix-style methods may be used.
See also
Notes
- ISO 80000-2, Section 9 "Operations", 2-9.6
- Cajori, Florian (1928). A history of mathematical notations. Vol. 1. Notations in Elementary Mathematics. The Open Court Company. pp. 242, 270–271. pp 270,271
- Weisstein, Eric W. "Division". mathworld.wolfram.com. Retrieved 2020-08-26.
- "Division". www.mathsisfun.com. Retrieved 2020-08-26.
- "6. Writing Systems and Punctuation". The Unicode® Standard: Version 10.0 – Core Specification (PDF). Unicode Consortium. June 2017. p. 280, Obelus.
- Korpela, Jukka (2006), Unicode Explained: Internationalize documents, programs, and web sites, O'Reilly Media, Inc., p. 397, ISBN 9780596101213
External links
- Jeff Miller: Earliest Uses of Various Mathematical Symbols
- Michael Quinion: Where our arithmetic symbols come from
The dictionary definition of division sign at Wiktionary