quality:corruption
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. 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 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, Poland and Russia, the ÷ sign was sometimes used to denote a range of values, and in Scandinavian countries it was, and sometimes still is, used as a negation sign: the Unicode Consortium has allocated a separate code point, U+2052 ⁒ COMMERCIAL MINUS SIGN for this usage uniquely; the exact form of the symbol displayed is typeface (font) dependent.