# Percent sign

%
Mathematical signs
arithmetic
Plus sign +
Minus sign - , ./.
Mark , ×
Divided sign : , ÷ , /
Plus minus sign ± ,
Comparison sign < , , = , , >
Root sign
Percent sign %
Analysis
Sum symbol Σ
Product mark Π
Difference sign , Nabla ,
Prime
Partial differential
Integral sign
Concatenation characters
Infinity symbol
geometry
Angle sign , , ,
Vertical , parallel ,
Triangle , square ,
Diameter sign
Set theory
Union , cut ,
Difference , complement ,
Element character
Subset , superset , , ,
Empty set
logic
Universal quantifier
Existential quantifier
Conjunction , disjunction ,
Negation sign ¬

The percent sign (%) is a mathematical symbol used to indicate percentages in texts and formulas . In DIN 5008 is determined that doing a between the number and the percent symbol space is set. The sign emerged over time from the contraction and stylization of the Italian per cento (of a hundred). In computer science , the percent sign is used in different roles, including as a character for the modulo operation, as an escape character , as a placeholder and as a comment character .

## history

Long before the invention of decimal fractions, there was a need for calculations in tenths or hundredths , for example for taxation or interest calculation . This led to its own notation , which was used instead of the decimal notation and is still used today in the form of the percent symbol.

As early as the 14th century, expressions such as “20 ᵱ 100” or “x ᵱ cento” (in today's notation 20% or 10%) can be found in Italian manuscripts. The abbreviation (p with struck through) stands for the Italian word per (German pro). In the course of the 15th century, the forms "ᵱ c o " and "ᵱ c̊" emerged from the per cento through contraction . Until the 17th century, the symbol developed from c̊ , consisting of two circles separated by a horizontal line. This symbol was initially preceded by a “per” or “ᵱ”, which then disappeared over time. ${\ displaystyle \ textstyle {\ frac {\ mathrm {o}} {\ mathrm {o}}}}$

However, the percentage sign only received general recognition from the middle of the 19th century. It was introduced by the Deutsche Reichsbahn in 1932 as a generally binding notation.

In modern notation, the percent sign is represented as a  % ligature with a slash instead of a horizontal line. In the typographic variant , the upper circle is connected to the line by a small arc. Derived from the percent sign, the degree sign ‰, which is formed by doubling of the lower circle, and the Pro-ten thousand characters ‱ which is produced by corresponding tripling. ${\ displaystyle \%}$

## use

### mathematics

In mathematics, the percent symbol is used to indicate percentages . Formally, the percent sign represents a one- digit combination with which the preceding number is divided by 100. For example is

${\ displaystyle 5 \, \% = {\ frac {5} {100}} = 0 {,} 05}$.

### Spellings

As with units of measurement , a protected space is placed between the number and the percentage sign (see notation of numbers ). The Duden recommends using a smaller, fixed space in between. In the case of derivations or compositions, the space in between does not apply (e.g. a 50% increase in sales , the 5% clause ).

According to the Chicago Manual of Style , however, no space should be placed between a number and a percentage sign in English-language texts. In Turkish, the percent sign is written in front of the number.

### Computer science

The percent sign is in the ASCII code at position 37 (hexadecimal 25). As such, it has many functions in computer science that no longer have anything in common with the original meaning:

### genealogy

In genealogy , the percent sign is used as an alternative to the symbol of divorce ⚮, see genealogical signs .

## Coding

The percent symbol and its modifications are encoded in computer systems as follows.

Coding in Unicode, HTML and LaTeX
character Unicode designation HTML Latex
% U+0025 percent sign Percent sign & # x25; & # 37; & percnt; \%
U+2030 per mille sign Alcohol symbol & # x2030; & # 8240; & permil; \textperthousand
U+2031 per ten thousand sign Per ten thousand characters & # x2031; & # 8241; & pertenk; \textpertenthousand
٪ U+066A arabic percent sign Arabic percent sign & # x066A; & # 1642;
؉ U+0609 arabic per mille sign Arabic alcohol symbol & # x0609; & # 1545;
؊ U+0610 arabic per ten thousand sign Arabic pro ten thousand sign & # x0610; & # 1546;
Not generally defined until HTML5 .

A distinction must be made between the percentage sign and the commercial minus sign ⁒ (U + 2052 commercial minus sign ) with dots instead of circles, which is similar to the Arabic percentage sign.

## literature

• David Eugene Smith : History of Mathematics . tape 2 . Courier Dover Publications, 1958, ISBN 0-486-20430-8 .
• David Eugene Smith: Rara Arithmetica: A Catalog of the Arithmetics Written Before the Year MDCI, with a Description of Those in the Library of George Arthur Plimpton of New York . Boston Ginn, 1908 ( online ).
• Johannes Tropfke : History of elementary mathematics in a systematic representation . First volume. Veit, Leipzig 1902, p. 106 ( online ).

## Individual evidence

1. DIN 5008 : 2020-03 Writing and design rules for text and information processing , section 10.7 percent and alcohol symbols
2. ^ David Eugene Smith: History of Mathematics . tape 2 . Courier Dover Publications, 1958, pp. 248 .
3. ^ David Eugene Smith: History of Mathematics . tape 2 . Courier Dover Publications, 1958, pp. 250 .
4. ^ David Eugene Smith: Rara Arithmetica . Boston Ginn, 1908, p. 437 .
5. ^ David Eugene Smith: Rara Arithmetica . Boston Ginn, 1908, p. 440 .
6. ^ David Eugene Smith: Rara Arithmetica . Boston Ginn, 1908, p. 441 .
7. Johannes Tropfke : History of elementary mathematics in a systematic representation . First volume. Veit, Leipzig 1902, p. 106 .
8. ^ Deutsche Reichsbahn-Gesellschaft (ed.): Official Gazette of the Reichsbahndirektion Mainz of March 19, 1932, No. 12. Announcement No. 163, p. 59.
9. International system of units, SI brochure, 8th edition 2006, p. 46 or 134 online version (PDF file, 3.9 MB)
10. Duden, spelling of the German language, guidelines for typesetting, percentage and alcohol symbols.
11. ^ The Chicago Manual of Style Online. University of Chicago, accessed July 7, 2013 .
12. ^ Herbert Jansky: Textbook of the Turkish language . Otto Harrassowitz, 1970, p. 48 .
13. Character Entity Reference Chart. W3C, July 25, 2008, accessed March 18, 2015 .
14. Scott Pakin: The Comprehensive LaTeX Symbol List. (PDF, 8.7 MB) January 19, 2017, p. 13 , archived from the original on September 28, 2017 ; Retrieved on September 28, 2017 (English, linking the original results in a mirror of CTAN , the archive link compare file: Comprehensive LaTeX Symbol list.pdf ).