||This article may contain excessive, poor, or irrelevant examples. (March 2010)|
|Factorization||2 · 5|
|Divisors||1, 2, 5, 10|
|Roman numeral (unicode)||X, x|
10 (ten i//) is an even natural number following 9 and preceding 11. Ten is the base of the decimal numeral system, by far the most common system of denoting numbers in both spoken and written language. The reason for the choice of ten is assumed to be that humans have ten fingers (digits).
In common usage and derived terms 
- A collection of ten items (most often ten years) is called a decade.
- The ordinal adjective is denary.
- Increasing a quantity by one order of magnitude is most widely understood to mean multiplying the quantity by ten.
- To reduce something by one-tenth is to decimate. (In ancient Rome, the killing of one in ten soldiers in a cohort was the punishment for cowardice or mutiny; or, one-tenth of the able-bodied men in a village as a form of retribution, thus causing a labor shortage and threat of starvation in agrarian societies.)
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In mathematics 
Ten is a composite number, its proper divisors being 1, 2 and 5. Ten is the smallest noncototient, a number that cannot be expressed as the difference between any integer and the total number of coprimes below it.
Ten is the second discrete semiprime (2.5) and the second member of the (2.q) discrete semiprime family. Ten has an aliquot sum σ(n) of 8 and is accordingly the first discrete semiprime to be in deficit. All subsequent discrete semiprimes are in deficit. The aliquot sequence for 10 comprises five members (10,8,7,1,0) with this number being the second composite member of the 7-aliquot tree.
Ten is a semi-meandric number.
Ten is the sum of the first three prime numbers, of the four first numbers (1 + 2 + 3 + 4), of the square of the two first odd numbers and also of the first four factorials (0! + 1! + 2! + 3!). Ten is the eighth Perrin number, preceded in the sequence by 5, 5, 7.
Ten is the number of n-Queens Problem solutions for n = 5.
Ten is the smallest number whose status as a possible friendly number is unknown.
In numeral systems 
Decimal system 
As is the case for any base in its system, ten is the first two-digit number in decimal and thus the lowest number where the position of a numeral affects its value. Any integer written in the decimal system can be multiplied by ten by adding a zero to the end (e.g. 855 * 10 = 8550).
Roman numerals 
The Roman numeral for ten is X (which looks like two V's [the Roman numeral for 5] put together); it is thought that the V for five is derived from an open hand (five digits displayed). Incidentally, the Chinese word numeral for ten, is also a cross: 十.
Positional numeral systems other than decimal 
The digit '1' followed by '0' is how the value of p is written in base p. (E.g. 16 in hexadecimal is 10.)
- Ten is a Harshad number in bases 2, 3, 5, 6, 9 and all others above.
- In bases 15, 18 and 30, ten is a 1-automorphic number (displayed as the numeral 'A')..
List of basic calculations 
In science 
The meaning "10" is part of the following terms:
Also, the number 10 plays a role in the following:
- The atomic number of neon.
- The number of hydrogen atoms in butane, a hydrocarbon.
- The number of spacetime dimensions in some superstring theories.
- The New General Catalogue object NGC 10, a magnitude 12.5 spiral galaxy in the constellation Sculptor.
- The Saros number of the solar eclipse series which began on -2467 February 28 and ended on -1169 April 18. The duration of Saros series 10 was 1298.1 years, and it contained 73 solar eclipses.
- The Saros number of the lunar eclipse series which began on -2454 June 17 and ended on -1138 August 15. The duration of Saros series 10 was 1316.2 years, and it contained 74 lunar eclipses.
In religion and philosophy 
- References in the Bible, Judaism and Christianity:
- The Ten Commandments of Exodus and Deuteronomy are considered a cornerstone of Judaism and Christianity.
- People traditionally tithed one-tenth of their produce. The practice of tithing is still common in Christian churches today, though it is disputed in some circles as to whether or not it is required of Christians.
- In Deuteronomy 26:12, the Torah commands Jews to give one-tenth of their produce to the poor (Maaser Ani). From this verse and from an earlier verse (Deut. 14:22) there derives a practice for Jews to give one-tenth of all earnings to the poor.
- Ten Plagues were inflicted on Egypt in Exodus 7-12
- Jews observe the annual Ten Days of Repentance beginning on Rosh Hashanah and ending on Yom Kippur.
- In Jewish liturgy, Ten Martyrs are singled out as a group.
- There are said to be Ten Lost Tribes of Israel (those other than Judah and Benjamin)
- There are Ten Sephirot in the Kabbalistic Tree of Life
- The Bible records 10 generations between Adam and Noah, and 10 generations between Noah and Abraham
- In Judaism, ten men are the required quorum, called a minyan, for prayer services.
In money 
Most countries issue coins and bills with a denomination of 10 (See e.g. 10 dollar note). Of these, the dime, with the value of ten cents, or one tenth of a dollar, derives its name from the meaning "one-tenth" - see Dime (United States coin)#Denomination history and etymology.
In music 
- The interval of a major tenth is an octave plus a major third.
- The interval of a minor tenth is an octave plus a minor third.
- The title of quite a few albums. See Ten (album).
- "Ten lords a-leaping" is the gift on the tenth day of Christmas in the carol "The Twelve Days of Christmas"
In sports and games 
The meaning "10" is part of the following terms:
- decathlon, a combined event in athletics consisting of ten track and field events.
Also, the number 10 plays a role in the following:
- In American football, the end zones are 10 yards deep.
- In association football, the number 10 is traditionally worn by the team's playmaker. This use has led to "Number 10" becoming a synonym for that particular player, even if he or she does not wear that number.
- In Australian rules football, considered the break even amount of games won in a regular 22 game season.
- In baseball, 10 is the minimum number of players on the field at any given time during play (including the batter).
- In basketball:
- The top of the rim (goal) is 10 feet from the floor.
- In standard full-court basketball, there are 10 players on the court (5 on each team).
- In blackjack, the Ten, Jack, Queen and King are all worth 10 points.
- In cricket, 10 is the number of wickets required to be taken by the bowling side for the batting side to be bowled out.
- In gridiron football, 10 is the number of yards the offense must advance to maintain possession in a single set of downs—four in American and three in Canadian.
- In most rugby league competitions, the number 10 is worn by one of the two starting props. (One exception to this rule is the European Super League, which uses static squad numbering.)
- In rugby union, the starting fly-half wears the 10 shirt.
- In ten-pin bowling, 10 pins are arranged in a triangular pattern and there are 10 frames per game.
- The highest score possible in Olympics gymnastics competitions.
- Driving a racing car at ten-tenths is driving as fast as possible, on the limit.
- In Major League Baseball:
- The Chicago Cubs, for Hall of Famer Ron Santo.
- The Cincinnati Reds, for Hall of Fame manager Sparky Anderson.
- The Kansas City Royals, for manager Dick Howser.
- The Minnesota Twins, for manager Tom Kelly.
- The Montreal Expos, first for Rusty Staub and later for Hall of Famer Andre Dawson. The team has since relocated and become the Washington Nationals; after initially announcing that it would reissue numbers retired in Montreal, the team reversed itself.
- The New York Yankees, for Hall of Famer Phil Rizzuto, who went on to spend four decades as a Yankees radio and TV broadcaster.
- The St. Louis Cardinals, for manager Tony La Russa.
- The Atlanta Braves have announced they will retire the number for Chipper Jones on June 28, 2013.
- In the NBA:
- The Boston Celtics, for Jo Jo White.
- The Chicago Bulls, for Bob Love.
- The Detroit Pistons, for Hall of Famer Dennis Rodman. Greg Monroe, who currently wears the number, is allowed to continue wearing it.
- The Miami Heat, for Tim Hardaway.
- The New York Knicks, for Hall of Famer Walt Frazier, who also served as a Knicks broadcaster after his playing career.
- The Philadelphia 76ers, for Maurice Cheeks, who also served as the team's head coach.
- The Seattle SuperSonics, for Nate McMillan, who also served as the team's head coach. The team has since relocated to become the Oklahoma City Thunder, but the Thunder have yet to issue any number retired by the franchise in Seattle.
- The Washington Wizards, for Hall of Famer Earl Monroe, who played for the team in its past incarnation as the Baltimore Bullets.
- In the NFL:
- In the NHL:
- The Carolina Hurricanes, for Hall of Famer Ron Francis.
- The Detroit Red Wings, for Hall of Famer Alex Delvecchio.
- The Montreal Canadiens, for Hall of Famer Guy Lafleur.
- The first NHL incarnation of the Winnipeg Jets, for Hall of Famer Dale Hawerchuk. The Jets have since reincarnated and have continued to honour the numbers retired by the initial franchise in Winnipeg.
- The Toronto Maple Leafs have a policy of not retiring numbers unless the player honoured either died or suffered a career-ending incident while a member of the team. Other players whose numbers would otherwise be retired instead have their numbers enshrined by the team as "Honoured Numbers", which remain in circulation for future players. The number 10 is currently honoured for Hall of Famers Syl Apps and George Armstrong.
- The jersey number 10 has also been retired by the men's basketball program of the University of North Carolina for Lennie Rosenbluth.
In technology 
- Ten-codes are commonly used on emergency service radio systems.
- Ten refers to the "meter band" on the radio spectrum between 28 and 29.7 MHz, used by amateur radio.
- ASCII and Unicode code point for line feed
- In MIDI, Channel 10 is reserved for unpitched percussion instruments.
- In the Rich Text Format specification, all language codes for regional variants of the Spanish language are congruent to 10 mod 256.
- In Mac OS X, the F10 function key tiles all the windows of the current application and grays the windows of other applications.
- The IP addresses in the range 10.0.0.0/8 (meaning the interval between 10.0.0.0 and 10.255.255.255) is reserved for use by Private networks by RFC 1918.
In other fields 
- Blake Edwards' 1979 movie 10 (film).
- Series on HBO entitled "1st & Ten" which aired between December 1984 and January 1991.
- Series on ESPN and ESPN2 entitled 1st and 10 which launched on ESPN in October 2003 to 2008 and moved to ESPN2 from 2008 to present.
- Counting from one to ten before speaking is often done in order to cool one's temper.
- In astrology, Capricorn is the 10th astrological sign of the Zodiac.
- In Chinese astrology, the 10 Heavenly Stems, refer to a cyclic number system that is used also for time reckoning.
- An online show hosted by Microsoft.
- A 1977 short documentary film Powers of Ten depicts the relative scale of the Universe in factors of ten (orders of magnitude).
- CBS has a game show called Power of 10, where the player's prize goes up and down by either the previous or next power of ten.
- "Ten Chances" is one the pricing games on The Price is Right.
- There are ten official inkblots in the Rorschach inkblot test.
- The traditional Snellen chart uses 10 different letters.
- Number of kingdoms in Five Dynasties and Ten Kingdoms Period
- House number of 10 Downing Street.
- The number of Provinces in Canada.
- The designation of United States Interstate 10, a freeway that runs from California to Florida.
- Number of dots in a tetractys.
- The number of the French department Aube.
- The number of regions in Ghana.
- The state number of Virginia.
See also 
|Look up ten in Wiktionary, the free dictionary.|
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