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 is not universal and the symbol has different meanings in other countries. Consequently, its use to denote division is deprecated in the ISO 80000-2 standard for notations used in mathematics, science and technology.

In mathematics

The

obelus An obelus (plural: obeluses or obeli) is a term in codicology and latterly in typography that refers to a historical annotation mark which has resolved to three modern meanings: * Division sign * Dagger * Commercial minus sign (limited g ...

, a historical

glyph A glyph ( ) is any kind of purposeful mark. In typography, a glyph is "the specific shape, design, or representation of a character". It is a particular graphical representation, in a particular typeface, of an element of written language. A ...

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 Algebra is a branch of mathematics that deals with abstract systems, known as algebraic structures, and the manipulation of expressions within those systems. It is a generalization of arithmetic that introduces variables and algebraic ope ...

book ' by Johann Rahn, although previous writers had used the same symbol for subtraction.
pp 270,271
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). The ISO 80000-2 standard for mathematical notation in science and technology recommends only the solidus or "fraction bar" for division, or the "colon" for

ratio In mathematics, a ratio () shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ...

s; it says that the sign "should not be used" for division.BS ISO 80000-2, "Quantities and units Part 2: Mathematical signs and symbols to be used in the natural sciences and technology", Section 9 "Operations", 2-9.6 In

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

and

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

, the sign was sometimes used to denote a range of values, and in

Scandinavia Scandinavia is a subregion#Europe, subregion of northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. ''Scandinavia'' most commonly refers to Denmark, Norway, and Sweden. It can sometimes also ...

n countries it was, and sometimes still is, used as a negation sign: the Unicode Consortium has allocated a separate

code point A code point, codepoint or code position is a particular position in a Table (database), table, where the position has been assigned a meaning. The table may be one dimensional (a column), two dimensional (like cells in a spreadsheet), three dime ...

, for this usage uniquely; the exact form of the symbol displayed is typeface (font) dependent.

In computer systems

Encoding

The symbol was assigned to

0xF7 in ISO 8859-1, as the "division sign". This encoding was transferred to

Unicode Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...

as U+00F7. In

HTML Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It defines the content and structure of web content. It is often assisted by technologies such as Cascading Style Sheets ( ...

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

provides various division symbols:

Notes

External links

Jeff Miller: ''Earliest Uses of Various Mathematical Symbols''
{{navbox punctuation Mathematical symbols Typographical symbols Division (mathematics) Ancient Greek punctuation

In mathematics

In computer systems

Encoding

See also

Notes

External links