؋ ₳ ฿ ₿ ₵ ¢ ₡ ₢ $ ₫
₯ ֏ ₠ € ƒ ₣ ₲ ₴ ₭
₺ ₾ ₼ ℳ ₥ ₦ ₧ ₱ ₰ £
元 圆 圓 ﷼ ៛ ₽ ₹ ₨ ₪ ৳ ₸
₮ ₩ ¥ 円
Uncommon typography
asterism
⁂
fleuron, hedera
❧
index, fist
☞
interrobang
‽
irony punctuation
⸮
lozenge
◊
tie
⁀
Related
Diacritics
Logic symbols
Whitespace characters
In other scripts
Chinese
Hebrew
Japanese
Korean
Category
Portal
Book
v
t
e
The multiplication sign
The multiplication sign, also known as the times sign or the dimension
sign is the symbol ×. While similar to the lowercase letter x, the
form is properly a rotationally symmetric saltire.[1]
Contents
1 Uses
2 History
3 Similar notations
4 In computer software
5 Unicode
6 See also
7 References
8 External links
Uses[edit]
In mathematics, the symbol × has a number of uses, including
Multiplication
Multiplication of two scalar numbers, where it is read as "times" or
"multiplied by"
Cross product
Cross product of two vectors, where it is usually read as "cross"
Cartesian product
Cartesian product of two sets, where it is usually read as "cross"
Geometric dimension of an object, such as noting that a room is 10
feet × 12 feet in area, where it is usually read as "by" (for
example: "10 feet by 12 feet")
Dimensions of a matrix, where it is usually read as "by"
In biology, the multiplication sign is used in a botanical hybrid
name, for instance
Ceanothus papillosus
Ceanothus papillosus × impressus (a hybrid between
C. papillosus and C. impressus) or
Crocosmia × crocosmiiflora
Crocosmia × crocosmiiflora (a
hybrid between two other species of Crocosmia). However, the
communication of these hybrid names with a standard non-multiplication
"x" is common when the actual "×" symbol is not readily available.
The multiplication sign is also used by historians for an event
between two dates. When employed between two dates, for example 1225
and 1232, 1225×1232 means "no earlier than 1225 and no later than
1232". It can also be used in a date range: 1225×1232–1278.[2]
History[edit]
The multiplication sign (×), often attributed to William Oughtred
(who first used it in an appendix to the 1618 edition of John Napier's
Mirifici Logarithmorum Canonis Descriptio), apparently had been in
occasional use since the mid 16th century.[3]
Similar notations[edit]
Main article: Multiplication: Notation and terminology
The letter "x" is sometimes used in place of the multiplication sign.
This is considered incorrect in mathematical writing.
In algebraic notation, widely used in mathematics, a multiplication
symbol is usually omitted wherever it would not cause confusion: "a
multiplied by b" can be written as ab or a b.
Other symbols can also be used to denote multiplication, often to
reduce confusion between the multiplication sign × and the commonly
used variable x. In many non-Anglophone countries, rather than ×, the
primary symbol for multiplication is U+22C5 ⋅ dot operator, for
which the interpunct · may be substituted as a more accessible
character. This symbol is also used in mathematics wherever
multiplication should be written explicitly, such as in "ab = a⋅2
for b = 2"; this usage is also seen in English-language texts. In some
languages (especially Bulgarian[citation needed]) and French[citation
needed] the use of full stop as a multiplication symbol, such as a.b,
is common.
Historically, computer language syntax was restricted to the ASCII
character set; in the absence of the × character, U+002A * Asterisk
became the de facto standard notation of the multiplication operator
in computing. This selection is still reflected in the standard
numeric keypad, where the arithmetic operations of addition,
subtraction, multiplication, and division are represented by the +, -,
*, and / keys, respectively.
In computer software[edit]
The × symbol is listed in the Latin-1 Supplement character set and is
U+00D7 × MULTIPLICATION SIGN (HTML × ·
×) in Unicode. It can be invoked in various operating
systems as per the table below.
A monadic × symbol is used by the APL programming language to denote
the sign function.
There is a similar character ⨯ at U+2A2F, but this is not always
considered identical to U+00D7, as U+2A2F is intended to explicitly
denote the cross product of two vectors.
Mac OS X
in Character Palette, search for MULTIPLICATION SIGN[4][5]
HTML, SGML, XML
× and ×
Microsoft Windows
Alt Gr++
Alt+0215
Alt+0D7[6]
Unix-like
Ctrl+⇧ Shift+U00D7
Compose X X
OpenOffice.org
times
TeX
times
Unicode
U+00D7
Unicode[edit]
In Unicode, the basic character is U+00D7 × MULTIPLICATION SIGN
(HTML × · ×)
Other variants are encoded:
U+2297 ⊗ CIRCLED TIMES (HTML ⊗ · ⊗)
U+2715 ✕ MULTIPLICATION X (HTML ✕)
U+2716 ✖ HEAVY MULTIPLICATION X (HTML ✖)
U+2A09 ⨉ N-ARY TIMES OPERATOR (HTML ⨉)
U+2A2F ⨯ VECTOR OR CROSS PRODUCT (HTML ⨯)
U+2A30 ⨰ MULTIPLICATION SIGN WITH DOT ABOVE (HTML ⨰)
U+2A31 ⨱ MULTIPLICATION SIGN WITH UNDERBAR (HTML ⨱)
U+2A34 ⨴ MULTIPLICATION SIGN IN LEFT HALF CIRCLE
(HTML ⨴)
U+2A35 ⨵ MULTIPLICATION SIGN IN RIGHT HALF CIRCLE
(HTML ⨵)
U+2A36 ⨶ CIRCLED MULTIPLICATION SIGN WITH CIRCUMFLEX ACCENT
(HTML ⨶)
U+2A37 ⨷ MULTIPLICATION SIGN IN DOUBLE CIRCLE
(HTML ⨷)
U+2A3B ⨻ MULTIPLICATION SIGN IN TRIANGLE (HTML ⨻)
U+2AC1 ⫁ SUBSET WITH MULTIPLICATION SIGN BELOW
(HTML ⫁)
U+2AC2 ⫂ SUPERSET WITH MULTIPLICATION SIGN BELOW
(HTML ⫂)
See also[edit]
Komejirushi
List of mathematical symbols
References[edit]
^ Stallings, L. (2000). "A Brief History of Algebraic Notation".
School Science and Mathematics. 100 (5): 230–235.
doi:10.1111/j.1949-8594.2000.tb17262.x. ISSN 0036-6803.
^ New Hart's rules: the handbook of style for writers and editors,
Oxford University Press, 2005, p. 183,
ISBN 978-0-19-861041-0
^ Florian Cajori (1929), A History of Mathematical Notations, Dover
Books on Mathematics, pp. 251f.
^ "Archived copy". Archived from the original on 2010-01-09. Retrieved
2009-10-09.
^ "Archived copy". Archived from the original on 2007-10-25. Retrieved
2009-10-09.
^ "
Unicode
Unicode Character 'MULTIPLICATION SIGN' (U+00D7)". Fileformat.info.
Retrieved 2017-01-13.
External links[edit]
"Letter Database". Eki.ee. Retrieved 2017-01-13.
"
Unicode
Unicode Character 'MULTIPLICATION SIGN' (U+00D7)". Fileformat.info.
Retrieved 2017-01-13.
"
Unicode
Unicode Character 'VECTOR OR CROSS PRODUCT' (U+2A2F)".
Fileformat.info. Retrieved