×
Encyclopedia
The multiplication sign is the symbol ×. The symbol is similar to the lowercase letter x
X
X is the twenty-fourth letter in the basic modern Latin alphabet.-Uses:In mathematics, x is commonly used as the name for an independent variable or unknown value. The usage of x to represent an independent or unknown variable can be traced back to the Arabic word šay شيء = “thing,” used in Arabic...

 but is a more symmetric saltire
Saltire
A saltire, or Saint Andrew's Cross, is a heraldic symbol in the form of a diagonal cross or letter ex . Saint Andrew is said to have been martyred on such a cross....

, and has different uses. It is also known as St. Andrew's Cross and as the dimension sign.

In mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, the symbol
Symbol
A symbol is something which represents an idea, a physical entity or a process but is distinct from it. The purpose of a symbol is to communicate meaning. For example, a red octagon may be a symbol for "STOP". On a map, a picture of a tent might represent a campsite. Numerals are symbols for...

 × (read as times, multiplication sign or into sign) is primarily used to denote the
  • multiplication
    Multiplication
    Multiplication is the mathematical operation of scaling one number by another. It is one of the four basic operations in elementary arithmetic ....

     of two numbers (computer languages bound to the rudimentary ASCII
    ASCII
    The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

     set often use an asterisk
    Asterisk
    An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...

     (*) to replace the missing crosses
    Cross product
    In mathematics, the cross product, vector product, or Gibbs vector product is a binary operation on two vectors in three-dimensional space. It results in a vector which is perpendicular to both of the vectors being multiplied and normal to the plane containing them...

     (×) and dots
    Dot product
    In mathematics, the dot product or scalar product is an algebraic operation that takes two equal-length sequences of numbers and returns a single number obtained by multiplying corresponding entries and then summing those products...

     (·)
  • cross product
    Cross product
    In mathematics, the cross product, vector product, or Gibbs vector product is a binary operation on two vectors in three-dimensional space. It results in a vector which is perpendicular to both of the vectors being multiplied and normal to the plane containing them...

     of two vectors
  • Cartesian product
    Cartesian product
    In mathematics, a Cartesian product is a construction to build a new set out of a number of given sets. Each member of the Cartesian product corresponds to the selection of one element each in every one of those sets...

     of two sets
  • multiplication and the sign function
    Sign function
    In mathematics, the sign function is an odd mathematical function that extracts the sign of a real number. To avoid confusion with the sine function, this function is often called the signum function ....

    , as an APL operator
    Operator (programming)
    Programming languages typically support a set of operators: operations which differ from the language's functions in calling syntax and/or argument passing mode. Common examples that differ by syntax are mathematical arithmetic operations, e.g...

    .


The × symbol for multiplication was introduced by William Oughtred
William Oughtred
William Oughtred was an English mathematician.After John Napier invented logarithms, and Edmund Gunter created the logarithmic scales upon which slide rules are based, it was Oughtred who first used two such scales sliding by one another to perform direct multiplication and division; and he is...

 in 1631. It was chosen for religious reason to represent the cross. The symbol is encoded in Unicode at .

Similar notations

Many other symbols are used to denote multiplication, often to reduce confusion between the multiplication sign × and the commonly used variable x
X
X is the twenty-fourth letter in the basic modern Latin alphabet.-Uses:In mathematics, x is commonly used as the name for an independent variable or unknown value. The usage of x to represent an independent or unknown variable can be traced back to the Arabic word šay شيء = “thing,” used in Arabic...

. Nonetheless, the letter "x" is sometimes mistakenly used in place of the multiplication sign.

In many non-Anglophone countries, the · (middle dot or interpunct
Interpunct
An interpunct —also called an interpoint—is a small dot used for interword separation in ancient Latin script, which also appears in some modern languages as a stand-alone sign inside a word. It is present in Unicode as code point ....

) is the primary multiplication sign (instead of ×): "a multiplied by b" is written either explicitly as a·b or implicitly as ab depending on context.

In biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

, the multiplication sign is used in a botanical hybrid name
Hybrid name
In botanical nomenclature, a hybrid may be given a hybrid name, which is a special kind of botanical name. The ICBN provides the following options in dealing with a hybrid:...

, where it is read as "cross".

In computer software

The × symbol is listed in Unicode letterlike symbols
Letterlike Symbols
Letterlike Symbols are graphemes which are constructed mainly from the glyphs of one or more letters.In Unicode, Letterlike Symbols are placed in the block U+2100–214F, as in the following table.-See also:*Mapping of Unicode characters...

 and is U+00D7 in Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

. It can be invoked in various operating systems as per the table below.

There is a similar character ⨯ at U+2A2F, but this is not always considered identical to U+00D7, as it is intended to explicitly denote the cross product
Cross product
In mathematics, the cross product, vector product, or Gibbs vector product is a binary operation on two vectors in three-dimensional space. It results in a vector which is perpendicular to both of the vectors being multiplied and normal to the plane containing them...

 of two vectors.

In computers, the *
Asterisk
An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...

 symbol is used most often for multiplication since the ⨯ symbol does not exist on most keyboards.

Apple Macintosh in Character Palette, search for MULTIPLICATION SIGN
HTML × and ×
Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

Alt
Alt key
The Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...

 + 0215 or Alt
Alt key
The Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...

 + 00D7
Microsoft Word
Microsoft Word
Microsoft Word is a word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS , the Apple Macintosh , the AT&T Unix PC , Atari ST , SCO UNIX,...

U+00D7
Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

/X Window
Alt + Shift + ; for ×, Alt + . for · or Compose
Compose key
A compose key, available on some computer keyboards, is a special kind of modifier key designated to signal the software to interpret the following sequence of two keystrokes as a combination in order to produce a character not found directly on the keyboard...

 x x for ×
OpenOffice.org
OpenOffice.org
OpenOffice.org, commonly known as OOo or OpenOffice, is an open-source application suite whose main components are for word processing, spreadsheets, presentations, graphics, and databases. OpenOffice is available for a number of different computer operating systems, is distributed as free software...

times
TeX
TeX
TeX is a typesetting system designed and mostly written by Donald Knuth and released in 1978. Within the typesetting system, its name is formatted as ....

\times
Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

U+00D7
XML
Extensible Markup Language
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

unknown

External links

  • http://www.eki.ee/letter/chardata.cgi?ucode=00D7
  • http://www.fileformat.info/info/unicode/char/00d7/index.htm (the general multiplication sign)
  • http://www.fileformat.info/info/unicode/char/2a2f/index.htm (the cross product sign)
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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