Division sign


The division sign is a symbol consisting of a short horizontal line with a dot above and another dot below, used to indicate mathematical division. However, this usage, though widespread in Anglophone countries, is not universal, and the symbol's use for division is not recommended in the ISO 80000-2 standard for mathematical notation.

In mathematics

The obelus, an historical glyph consisting of a horizontal line with one or more dots, was first used as a symbol for division in 1659 in the algebra book Teutsche Algebra by Johann Rahn. Some think 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 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.
In Italy and Russia, the sign is sometimes used to denote a range of values, in engineering contexts.
Historically, an oblique form of the obelus, , has also been used to represent subtraction in Northern Europe; such usage continued in some parts of Europe.

In computer systems

The symbol was assigned to code point 0xF7 in ISO 8859-1, as the "division sign" and has the code point U+00F7. In HTML, it can be encoded as or , or as.

Keyboard entry

In Microsoft Windows, this division sign is produced with Alt+0247 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 and . It may also be input using its Unicode code-point by pressing.
In LaTeX, the division sign is obtained by.
In Chrome OS . Otherwise, the Unix-style methods may be used.