Division sign
| ÷ | |
|---|---|
Division sign | |
| In Unicode | U+00F7 ÷ DIVISION SIGN (HTML ÷ · ÷) |
| Related | |
| See also | U+00D7 × MULTIPLICATION SIGN |
| Different from | |
| Different from | U+2052 ⁒ COMMERCIAL MINUS SIGN U+002B + PLUS SIGN U+2020 † DAGGER U+034B ͋ COMBINING HOMOTHETIC ABOVE |
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. 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.[1]
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]
The same symbol has been used to represent subtraction in north-eastern Europe: the Unicode Consortium has allocated a separate code point, U+2052 ⁒ COMMERCIAL MINUS SIGN for this usage uniquely;[6][7] 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.[8] 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 when an appropriate keyboard layout is in use. In classic Mac OS and macOS, it is produced with .
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 .
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 . Otherwise, the Unix-style methods may be used.
See also
Notes
- ↑ 1.0 1.1 ISO 80000-2, Section 9 "Operations", 2-9.6
- ↑ 2.0 2.1 Cajori, Florian (1928). A history of mathematical notations. 1. Notations in Elementary Mathematics. The Open Court Company. pp. 242, 270–271. https://archive.org/details/in.ernet.dli.2015.200372/page/n261/mode/2up. pp 270,271
- ↑ Weisstein, Eric W.. "Division" (in en). https://mathworld.wolfram.com/Division.html.
- ↑ "Division". https://www.mathsisfun.com/numbers/division.html.
- ↑ "6. Writing Systems and Punctuation". The Unicode® Standard: Version 10.0 – Core Specification. Unicode Consortium. June 2017. p. 280, Obelus. https://www.unicode.org/versions/Unicode10.0.0/ch06.pdf#G7935.
- ↑ Leif Halvard Silli. "Too narrowly defined: DIVISION SIGN & COLON". http://www.unicode.org/mail-arch/unicode-ml/y2012-m07/0053.html.
- ↑ Leif Halvard Silli. "Commercial minus as italic variant of division sign in German and Scandinavian context". https://www.unicode.org/mail-arch/unicode-ml/y2014-m01/0018.html.
- ↑ Korpela, Jukka (2006), Unicode Explained: Internationalize documents, programs, and web sites, O'Reilly Media, Inc., p. 397, ISBN 9780596101213, https://books.google.com/books?id=PcWU2yxc8WkC&pg=PA397
External links
- Jeff Miller: Earliest Uses of Various Mathematical Symbols
- Michael Quinion: Where our arithmetic symbols come from
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