Division sign explained

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Different From:


The division sign is a 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. 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.

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 German: Teutsche Algebra by Johann Rahn, although previous writers had used the same symbol for subtraction.[1] Some near-contemporaries believed that John Pell, who edited the book, may have been responsible for this use of the symbol. Other symbols for division include the slash or solidus, the colon, and the fraction bar (the horizontal bar in a vertical fraction).[2] [3] 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.[4]

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, 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. In HTML, it can be encoded as or (at HTML level 3.2), or as .

Unicode provides various division symbols:[8]

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+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 .

In ChromeOS (with International/Extended keyboard setting), the division sign is obtained by pressing . Otherwise, the Unix-style methods may be used.

See also

External links

Notes and References

  1. Book: Cajori, Florian . A history of mathematical notations . 1. Notations in Elementary Mathematics . The Open Court Company . 1928 . Florian Cajori . 242, 270–271 . pp 270,271
  2. Web site: Weisstein. Eric W.. Division. 2020-08-26. mathworld.wolfram.com. en.
  3. Web site: Division. 2020-08-26. www.mathsisfun.com.
  4. ISO 80000-2, Section 9 "Operations", 2-9.6
  5. Book: https://www.unicode.org/versions/Unicode10.0.0/ch06.pdf#G7935 . 280, Obelus . 6. Writing Systems and Punctuation . Unicode Consortium . The Unicode® Standard: Version 10.0 – Core Specification . June 2017.
  6. Web site: Too narrowly defined: DIVISION SIGN & COLON . Leif Halvard Silli . Unicode.org.
  7. Web site: Commercial minus as italic variant of division sign in German and Scandinavian context . Leif Halvard Silli . Unicode.org.
  8. Web site: Division symbol .