20 (number)

← 19 21 → 20
← 20 21 22 23 24 25 26 27 28 29 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	twenty
Ordinal	20th (twentieth)
Numeral system	vigesimal
Factorization
Divisors	1, 2, 4, 5, 10, 20
Roman numeral	XX
Binary	101002
Octal	248
Duodecimal	1812
Hexadecimal	1416

"Twenty" redirects here. For the village in England, see Twenty, Lincolnshire.

20 (twenty) is the natural number following 19 and preceding 21. A group of twenty units may also be referred to as a score.^[1]

Look up twenty in Wiktionary, the free dictionary.

[edit] In science

• The atomic number of calcium.
• The third Magic number (physics).

[edit] Biology

• The number of proteinogenic amino acids that are encoded by the standard genetic code.
• In some countries, the number 20 is used as an index in measuring visual acuity. 20/20 indicates normal vision at 20 feet, although it is commonly used to mean "perfect vision" (Note that this applies only to countries using the Imperial system. The metric equivalent is 6/6). When someone is able to see only after an event how things turned out, that person is often said to have had "20/20 hindsight".
• There are 20 baby teeth in the deciduous dentition.

[edit] In religion

• Age 20 is the age at which Levites in the time of King David were allowed "to do the work for the service of the house of the Lord", the Temple in Jerusalem (see First Chronicles Chapter 24, verses 24 and 27). In the time of Ezra and Nehemiah, following the Babylonian captivity, it was Levites from the age of 20 upwards who were assigned "to oversee the work of the house of the LORD" (Ezra Chapter 3, verse 8).

[edit] In sports

• 20 is the retired number of Pro Football Hall of Fame running back Barry Sanders, formerly of the Detroit Lions.
• The retired number of former baseball stars Frank Robinson, Mike Schmidt, Mark Fidrych and Lou Brock.
• 20 is the number of Tony Stewart's 2-time winning NASCAR NEXTEL Cup Series car.
• The Twenty20 Cup is a form of limited Overs Cricket where each team plays only 20 Overs.
• The number of NFL stars Ed Reed, Ronde Barber and Brian Dawkins.
• 20 is the number worn by NBA player Manu Ginobili of the San Antonio Spurs.
• 20 is the number worn by NBA point guard Gary Payton formerly of Seattle SuperSonics
• 20 is the iconic number worn by Soccer player Ole Gunnar Solskjær of Manchester United.
• 20 is the number worn by New York Yankees all-star catcher Jorge Posada.
• A twenty-game winner (pitcher) in baseball is acclaimed as having reached a milestone in a season. The most remarkable of 20-game winners was probably Hank Borowy, who won 10 games with the Yankees in 1945 before being put on waivers, then signed with the Cubs and won 11 more games playing the rest of the season. He had been in the World Series with the Yanks and played for Chicago in the '45 Series as well.
• Lukas Podolski, German National soccer player, wears number 20.
• Polish soccer player Zbigniew Boniek wore number 20 in the National Team.
• 20 is worn by NHL all-star goaltender Evgeni Nabokov of the San Jose Sharks.
• 20 is worn by the MLS Star Taylor Twellman of the New England Revolution.
• 20 is worn by NBA superstar Ray Allen, who currently plays for the Boston Celtics.
• 20 is worn by Portugal's midfielder Deco.
• 20 is worn by NFL player Thomas Jones of the New York Jets.
• 20 is worn by MLB player Carlos Quentin of the Chicago White Sox.
• 20 is the number of Rugby League premierships won by the South Sydney Rabbitohs.

[edit] In other fields

• The number of twenty can also be called a score (as Abraham Lincoln did in his Gettysburg Address).
• Twenty questions is a popular party game
• Twenty is the age of majority in Japanese tradition. Someone who is exactly twenty years old is described as hatachi
• The Twenty Year Curse refers to the pattern of presidents of the United States who were elected to office in 1840, 1860, 1880, 1900, 1920, 1940, and 1960 to die in office. This pattern ended with the 1980 presidency of Reagan, who survived his time in office and, notably, an attempted assassination.
• Bands with the number twenty in their name include Matchbox Twenty
• A 20-minute-long entertainment program shown before some films playing in United Artists movie theaters is called "The Twenty" (spelled "The 20wenty")
• Yan Tan Tethera is a 20-word jingle for counting sheep
• The ordinal adjective is vicenary
• 20/20 is a late-night newsmagazine program on the ABC network, that has been hosted by Barbara Walters, Hugh Downs, Elizabeth Vargas, and others
• In the roleplaying game Dungeons and Dragons (as well as other RPGs that use twenty-sided dice), twenty-sided dice play a pivotal role in gameplay, and to "roll a twenty" is significant to the point that it is sometimes used in other, usually related, contexts, similar to the use of "doubles" in reference to Monopoly.
• Cigarettes are usually packaged with 20 in each pack.
• "T" is the 20th letter in the alphabet.
• According to The Strokes in the song You Only Live Once there are 20 way to see the world, and 20 ways to start a fight.

20 is:

• Twenty, a village in Lincolnshire
• In the United States Constitution, $20 is the threshold value of civil disputes above which the right to trial by jury is preserved
• A denomination of U.S. dollar featuring Andrew Jackson's portrait
• A denomination of Pound sterling featuring Adam Smith's portrait
• The code for international direct dial phone calls to Egypt
• The designation of Interstate 20, a freeway that runs from Texas to South Carolina
• 20 (album), a 1988 album by Harry Connick, Jr.
• Twenty (album), a 1997 album by Lynyrd Skynyrd
• 20 (Terminaator album), a 2007 album by Terminaator
• Twenty (concert), a 2006 concert celebrating the 20th Anniversary of Regine Velasquez held at the Araneta Coliseum, Philippines. It was awarded Best Major Concert Act by the Aliw Awards.
• CB slang for "a place", being short for "10-20", used in reference to a person or object's location
• One of the TCP/IP ports used for File Transfer Protocol

[edit] Historical years

20 A.D., 20 B.C., 1920, 2020, etc.

[edit] References

1. ^ John H. Conway and Richard K. Guy, The Book of Numbers. New York: Copernicus (1996): 11. ""Score" is related to "share" and comes from the Old Norse "skor" meaning a "notch" or "tally" on a stick used for counting. ... Often people counted in 20s; every 20th notch was larger, and so "score" also came to mean 20."