This article may contain excessive, poor or irrelevant examples. You can improve the article by adding more descriptive text and removing less pertinent examples. See Wikipedia's guide to writing better articles for further suggestions. (March 2010)

Look up twenty in Wiktionary, the free dictionary.

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]

In mathematics[link]

An icosahedron has 20 faces

• 20 is a tetrahedral number as 20 = 1 + 3 + 6 + 10.
• 20 is the basis for vigesimal number systems.
• 20 is the third composite number comprising the product of a squared prime and a prime, and also the second member of the (2²)q family in this form.
• 20 has an aliquot sum of 22 (110% in abundance). Accordingly, 20 is the third abundant number and demonstrates an 8 member aliquot sequence; {20, 22, 14, 10, 8, 7, 1, 0}.
• 20 is the smallest primitive abundant number.
• 20 is the 4th composite number in the 7-aliquot tree. Two numbers have 20 as their aliquot sum; the discrete semiprime 34 and the squared prime 361. Only 2 other square primes are abundant 12 and 18.
• An icosahedron has 20 faces. A dodecahedron has 20 vertices.
• 20 can be written as the sum of three Fibonacci Numbers uniquely, i.e. 20 = 13 + 5 + 2.
• The product of the number of divisors and the number of proper divisors of 20 is exactly 20.
• 20 is the number of quarter or half turns required to optimally solve a Rubik's Cube in the worst case.
• 20 is the only number with more than one digit that can be written from base 2 to base 20 using only the digits 0 to 9.^[2]

In science[link]

• The atomic number of calcium.
• The third magic number in physics.
• The IAU shower number for Coma Berenicids.

Biology[link]

• 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.

In religion[link]

• 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).

In sports[link]

A standard dartboard is laid out as 20 sectors

• The jersey number 20 has been retired by several North American sports teams in honor of past playing greats:
  • In Major League Baseball:
    • The Arizona Diamondbacks, for Luis Gonzalez.
    • The Baltimore Orioles and Cincinnati Reds, both for Hall of Famer Frank Robinson.
    • The Kansas City Royals, for Frank White.
    • The Los Angeles Dodgers, for Hall of Famer Don Sutton.
    • The Philadelphia Phillies, for Hall of Famer Mike Schmidt.
    • The Pittsburgh Pirates, for Hall of Famer Pie Traynor.
    • The St. Louis Cardinals, for Hall of Famer Lou Brock.
    • The San Francisco Giants, for Hall of Famer Monte Irvin, who played for the team when it was the New York Giants.
  • In the NFL:
    • The Detroit Lions, for Hall of Famer Barry Sanders.
    • The New England Patriots, for Gino Cappelletti, who played for the team when it was known by its original name of the Boston Patriots.
  • In the NBA:
    • The Portland Trail Blazers, for Maurice Lucas.
  • In the NHL:
    • The Los Angeles Kings, for Hall of Famer Luc Robitaille.
  • In the MLS:
    • The New England Revolution and USMNT, for 2005 MLS MVP Taylor Twellman, one of the best strikers to ever play in the league.
• In the NASCAR Sprint Cup Series, car #20 is currently owned by Joe Gibbs Racing. Tony Stewart won the Cup Series title twice in the #20 car while with Joe Gibbs Racing. After Stewart left the team in 2009 to drive for himself, rookie Joey Logano took over the car.
• Twenty20 is a form of limited overs cricket where each team plays only 20 overs.
• In rugby union, 20 national teams currently qualify for each edition of the Rugby World Cup.

Age 20[link]

• It is at this point that a person is no longer a teenager.
• Twenty is the age of majority in Japanese tradition.

In currency[link]

• A denomination of $US featuring Andrew Jackson's portrait
• A denomination of Pound sterling featuring Adam Smith's portrait

In films[link]

• 20/20 is a late-night newsmagazine program on ABC-TV
• In the 1974 sci-fi film Dark Star, Exponential Thermostellar Bomb number 20 threatens to detonate in the Dark Star's bomb bay
• A 20-minute-long program of advertisements and trailers shown before some films playing in American movie theaters is called "The Twenty" (spelled "The 20wenty")

In games[link]

• Twenty questions is a popular party game
• 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.

In music[link]

• Bands with the number twenty in their name include Matchbox Twenty
• 20 (Harry Connick, Jr. album), a 1988 album by Harry Connick, Jr.
• Twenty (Lynyrd Skynyrd 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.

In other fields[link]

• The number of twenty can also be called a score (as Abraham Lincoln did in his Gettysburg Address or Martin Luther King in his I Have a Dream speech).
• 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.
• In the United States Constitution, $20 is the threshold value of civil disputes above which the right to trial by jury is preserved
• Yan Tan Tethera is a 20-word jingle for counting sheep
• The ordinal adjective is vicenary
• There are 20 ounces in Venti size coffees at Starbucks coffee shops.

20 is:

• Twenty, Lincolnshire, a village
• The code for international direct dial phone calls to Egypt
• The designation of Interstate 20, a freeway that runs from Texas to South Carolina
• CB slang for "a place", being short for "10–20", used in reference to a person or object's location
• In the French and Portuguese education system, grades are given out of 20. Giving 20/20 is a very rare occasion.

Historical years[link]

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

References[link]

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."
2. ^ Sequence A131646 in The On-Line Encyclopedia of Integer Sequences

vep:20 (lugu)

Kris Kross was an American rap duo of the 1990s comprising Chris "Mac Daddy" Kelly and Chris "Daddy Mac" Smith. The duo are best known for their hit 1992 song "Jump", which was #1 on the Billboard Hot 100 for eight weeks and was certified double platinum as a single. Kris Kross was also noted for their fashion style, which consisted of wearing their clothing backwards. The duo sung the Rugrats Rap for Nickelodeon in 1993.

Career[link]

Atlanta natives Kelly (born August 11, 1978) and Smith (born January 10, 1979) were discovered in 1990 by 18-year-old Jermaine Dupri at an Atlanta shopping mall.^[1][2] Along with Dupri they signed a deal with Ruffhouse Records, and recorded their debut album Totally Krossed Out. Entirely produced by Dupri, Totally Krossed Out, was released March 31, 1992 and sold four million copies in the U.S. It included the hit single "Jump", which topped the Billboard Hot 100 for eight weeks.

The duo landed a spot on Michael Jackson's 1992 Dangerous World Tour, as well as a cameo appearance on Jackson's "Jam" music video. The music videos from their own album also experienced major success. The video for "Jump", directed by filmmaker Rich Murray went to No. 1 on MTV and sold over 100,000 copies as a VHS 'video single' and the video for their followup single "Warm It Up", also directed by Murray won a Billboard video award for "Best New Artist". In addition to this, they also made appearances in the music videos for Run-D.M.C.'s "Down with the King" and TLC's "Hat 2 Da Back". They were also featured in an episode of A Different World, and the closing musical act on May 29, 1992 episode of In Living Color.

In 1992, a video game was released starring the pair titled Kris Kross: Make My Video. It was released on the Sega CD system, and consisted of the player editing together the group's music videos to a few of their hit songs—using portions of the original music videos, stock footage, and general video animation effects. Players were prompted before each edit session to make sure to have certain footage compiled into the video. The game was released only in the United States to poor sales figures and dismal reviews. It was ranked 18th on Electronic Gaming Monthly's list of the "20 Worst Games of All Time".^[3]

Kris Kross recorded the Rugrats Rap for Rugrats ( A Nickelodeon cartoon) for Nickelodeon in 1993. The song is available on the Rugrats Chuckie the Brave VHS and The Best of Nicktoons CD which is a compilation album of theme songs and other material from several Nicktoons that was released by Nickelodeon and Rhino Records in 1998.

Kris Kross made a cameo appearance in Ted Demme's 1993 film Who's the Man?, which starred Ed Lover and Doctor Dré of Yo! MTV Raps fame.

Their second album, Da Bomb (1993), was certified platinum, and spawned the hit "Alright", although it failed to match their earlier success. Most of their songs had been directed at rivals Da Youngstas, Illegal and Another Bad Creation. A third album, Young, Rich & Dangerous, was released in early 1996 and was certified gold. It spawned the two hits "Tonite's tha Night" and "Live and Die for Hip Hop".

Discography[link]

Studio albums[link]

Remix albums[link]

Compilation albums[link]

Singles[link]

• US: Gold^[18]

References[link]

External links[link]

• One Life Entertainment Chris Smith's official website
• Chris Kelly at BlackHistoryDaily.com