To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
Show all languages
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.

From Wikipedia, the free encyclopedia

7 (seven) is the natural number following 6 and preceding 8.


In fact, if one sorts the digits in the number 142,857 in ascending order, 124578, it is possible to know from which of the digits the decimal part of the number is going to begin with. The remainder of dividing any number by 7 will give the position in the sequence 124578 that the decimal part of the resulting number will start. For example, 628 ÷ 7 = 89 5/7; here 5 is the remainder, and would correspond to number 7 in the ranking of the ascending sequence. So in this case, 628 ÷ 7 = 89.714285. Another example, 5238 ÷ 7 = 748 2/7, hence the remainder is 2, and this corresponds to number 2 in the sequence. In this case, 5238 ÷ 7 = 748.285714.
Graph of the probability distribution of the sum of 2 six-sided dice
Graph of the probability distribution of the sum of 2 six-sided dice

Basic calculations

Multiplication 1 2 3 4 5 6 7 8 9 10 15 25 50 100 1000
7 × x 7 14 21 28 35 42 49 56 63 70 105 175 350 700 7000
Division 1 2 3 4 5 6 7 8 9 10
11 12 13 14 15
7 ÷ x 7 3.5 2.3 1.75 1.4 1.16 1 0.875 0.7 0.7
0.63 0.583 0.538461 0.5 0.46
x ÷ 7 0.142857 0.285714 0.428571 0.571428 0.714285 0.857142 1 1.142857 1.285714 1.428571
1.571428 1.714285 1.857142 2 2.142857
Exponentiation 1 2 3 4 5 6 7 8 9 10
7x 7 49 343 2401 16807 117649 823543 5764801 40353607 282475249
x7 1 128 2187 16384 78125 279936 823543 2097152 4782969 10000000
Radix 1 5 10 15 20 25 30 40 50 60 70 80 90 100
110 120 130 140 150 200 250 500 1000 10000 100000 1000000
x7 1 5 137 217 267 347 427 557 1017 1147 1307 1437 1567 2027
2157 2317 2447 2607 3037 4047 5057 13137 26267 411047 5643557 113333117

Evolution of the glyph

In the beginning, various Hindus wrote 7 more or less in one stroke as a curve that looks like an uppercase J vertically inverted. The western Ghubar Arabs' main contribution was to make the longer line diagonal rather than straight, though they showed some tendencies to making the character more rectilinear. The eastern Arabs developed the character from a 6 lookalike into an uppercase V lookalike. Both modern Arab forms influenced the European form, a two-stroke character consisting of a horizontal upper line joined at its right to a line going down to the bottom left corner, a line that is slightly curved in some font variants. As is the case with the European glyph, the Cham and Khmer glyph for 7 also evolved to look like their glyph for 1, though in a different way, so they were also concerned with making their 7 more different. For the Khmer this often involved adding a horizontal line above the glyph.[9] This is analogous to the horizontal stroke through the middle that is sometimes used in handwriting in the Western world but which is almost never used in computer fonts. This horizontal stroke is, however, important to distinguish the glyph for seven from the glyph for one in writings that use a long upstroke in the glyph for 1. In some Greek dialects of early 12th century the longer line diagonal was drawn in a rather semicircular transverse line.

On the seven-segment displays of pocket calculators and digital watches, 7 is the number with the most common glyph variation (1, 6 and 9 also have variant glyphs). Most calculators use three line segments, but on Sharp, Casio, and a few other brands of calculators, 7 is written with four line segments because, in Japan, Korea and Taiwan 7 is written as ① in the illustration to the right.

While the shape of the 7 character has an ascender in most modern typefaces, in typefaces with text figures the character usually has a descender, as, for example, in


Most people in Continental Europe,[10] and some in Britain and Ireland as well as Latin America, write 7 with a line in the middle ("7"), sometimes with the top line crooked. The line through the middle is useful to clearly differentiate the character from the number one, as the two can appear similar when written in certain styles of handwriting. This glyph is used in official handwriting rules for primary school in Russia, Ukraine, Bulgaria, Poland, other Slavic countries,[11] France, Italy, Belgium, Finland,[12] Romania, Germany, Greece,[13] and Hungary.[14][not in citation given]

Automotive and transportation

Classical world

Classical antiquity

Commerce and business

Food and beverages

  • 7 Up is the name of a popular soft drink.

Media and entertainment





  • Lotto Super 7, a Canadian-lottery game that had its final drawing September 18, 2009.
  • Sevens, a card game.
  • Seven is the sum of any two opposite sides on a standard six-sided die.
  • In the game of craps, a dice roll of 7 on the come-out constitutes a "natural" and the Pass line wins immediately. However, if the shooter (dice thrower) rolls a 4, 5, 6, 8, 9, or 10 on the come-out roll, that number becomes his "point'. Now, the shooter must repeat his point before he throws a seven. If he repeats his point, the Pass line wins. If he rolls a seven, not only does the Pass line lose, the shooter loses control of the dice. This is called a "seven-out".

Video games



  • The number of notes in the traditional Western diatonic scale (major or minor).
  • In music, the Roman numeral vii is the leading tone (vii°) or subtonic (VII) scale degree, chord (leading-tone seventh chord or secondary leading-tone chord), or diatonic function, when distinguished V = major and v = minor.
  • The original diameter in inches of the 45rpm format gramophone record.
  • There are seven musicians in a septet or a septuor.
  • There are seven basic swaras [saptaswaras] in Indian Carnatic music.
  • "7" is a song by Prince and The New Power Generation, from the 1992 Love Symbol Album.
  • 7 is a 2003 Enrique Iglesias album.
  • 7 (Mick Thompson) is one of the guitarists for popular metal band Slipknot.
  • Sweet 7 is an album by Sugababes.
  • The number of dastgahs in Persian traditional music.
  • Seventh son of a Seventh son is the 7th album of the English heavy metal band Iron Maiden, brought out in 1988.
  • Sevens is the 7th album by Country singer Garth Brooks, released in 1997, consisting of 14 songs(2 sets of 7).
  • "Seven" is a song by Megadeth on their 1999 album Risk.
  • UK-based alt-rock band, Take The Seven (TTVII).
  • "The Munificent Seven" is the appended parenthetical title for the song "Love Is Stronger Than Justice" on Sting's 1993 album Ten Summoner's Tales.
  • "Seven" is a song on David Bowie's album Hours.
  • Seven Swans is the name of the 2004 album by Sufjan Stevens.
  • 7 is an alias of Mexican musician Juan Son.
  • 7 (O.S.T.R. album) is the seventh album of O.S.T.R.


  • A heptathlon is a combined event of seven running, jumping and throwing disciplines for both men's and women's athletics.
  • Rugby sevens is a variant of union and league that contains only seven players per side instead of the standard 15 (union) or 13 (league).
  • In the standard rugby union bonus points system, a team is awarded a bonus point in the league standings if it loses a game by 7 or fewer points.
  • In baseball:
  • In basketball:
    • The standard ball used for full-court men's play is designated as "size 7".
    • In the rule sets used for US college men's play and US high schools for both sexes, a team begins shooting bonus free throws once its opponent has committed 7 personal fouls in a half.
Jersey numbers
  • In association football, the right midfielder traditionally wears the number 7.
  • In rugby league, the jersey number 7 is worn by the starting scrum-half/halfback in most competitions (but not in the Super League, which uses static squad numbering).
  • In rugby union, the jersey number 7 is worn by the starting openside flanker. (Some teams use "left" and "right" flankers instead of "openside" and "blindside", with 7 being worn by the starting right flanker.)
Number of players
  • In cross country running, a team traditionally consists of seven athletes.
  • In team handball, the number of players on each team including the goalkeeper.
  • In netball, each team has seven players on the court.
  • In Ultimate, each team has seven players on the field.
  • In water polo, each team is allowed to have a maximum of seven players, one of them a goalkeeper, in the playing area of the pool at any given time.


Networks and stations

  • The circle 7 logo used by numerous ABC network O&O stations in the U.S. (In the late 1940s, ABC arranged for its five original, founding O&O TV stations to broadcast on channel 7.)
  • Maximum number of VHF broadcast channels available in any TV market in the United States of America; they are channels 2, 4, 5, 7, 9, 11, and 13 in the Greater New York City and Los Angeles-Long Beach SMSAs.
  • ProSieben (sieben being German for seven), a television network in Germany
  • Seven Network, a television network in Australia.
  • Trans7 (formerly TV7 before taken over by Trans Corporation), a television network in Indonesia.
  • GMA 7 (DZBB-TV channel 7 In Metro Manila) a television network in the Philippines.



  • The traditional count of Basque provinces as expressed in the slogan Zazpiak Bat, translates as "the seven [are] one" and refers to the seven Basque traditional provinces.
  • The figurative number of seas.
  • The Seven Virgins mountain range in Sri Lanka, which was the scene of an air disaster on December 4, 1974, involving a DC-8 Series 55F passenger jetliner operated by the charter company Martinair, which left 191 dead.
  • The Sevens (sometimes typeset as "7he Sevens"), a rugby union stadium in Dubai, UAE and home to the Dubai Sevens tournament.

Religion and mythology

Old Testament

  • Seven Hebrew words of Bereishit 1:1 / Genesis 1:1 (28 letters).
Seven Days of Creation - 1765 book
Seven Days of Creation - 1765 book

The number seven in the seven days of Creation is typological and the number seven appears commonly elsewhere in the Bible. These include:

  • Seven days of Creation (Genesis 1) e.g., God rested on and sanctified the seventh day (Sabbath).
  • Anyone who dares to kill Cain "will suffer vengeance seven times over" (Genesis 4:15).
  • Lamech in his "Song of the Sword" claims that "if Cain shall be avenged sevenfold", he himself shall be "seventy-sevenfold" (Genesis 4:24).
  • Noah is commanded to bring seven pairs of every clean animal onto the ark (Genesis 7:2).
  • Seven years of plenty and seven years of famine in Pharaoh's dream (Genesis 41).
  • In regards to the sin sacrifice, the anointed priest was to sprinkle the bullock's blood seven times before the LORD (Leviticus 4:6).
  • Seven days of the feast of Passover (Exodus 13:3–10).
  • Seven-day week and the pattern concerning distribution and use of manna (Exodus 16).
  • The Menorah (Hebrew: מנורה‎), is a seven-branched candelabrum lit by olive oil in the Tabernacle and the Temple in Jerusalem (Exodus 25).
  • Seven-year cycle around the years of Jubilee (Leviticus 25).
  • Jericho's walls fall on the seventh day after seven priests with seven trumpets march around the city seven times (Joshua 6:8).
  • King David had seven older brothers (1 Samuel 16).
  • The child sneezed seven times after Elisha raised him from the dead (2 Kings 4:35).
  • Seven things that are detestable to the LORD (Proverbs 6:16–19).
  • Seven Pillars of the House of Wisdom (Proverbs 9:1).
  • The woman with seven sons in 2 Maccabees.
  • Gad, whose name means good luck, is the seventh son of Jacob. Areli is the seventh son of Gad (Genesis 46:16). Chronicles lists David as the seventh son of Jesse (1 Chronicles 2:15). An unnamed eighth individual appeared among the seven in 1 Samuel 16, then David as the youngest is brought before Samuel.

New Testament

Seven lampstands in The Vision of John on Patmos by Julius Schnorr von Carolsfeld, 1860.
Seven lampstands in The Vision of John on Patmos by Julius Schnorr von Carolsfeld, 1860.

Other sevens in Christian knowledge and practice include:


  • The Sanskrit word sapta refers to number seven.
  • Indian Music has "Saptak Swaras", seven octats (sa re ga ma pa dha ni) which are basics of music, using which hundreds of Ragas are composed.
  • Celestial group of seven stars (7 Classical Planets) are named as "Sapta Rishi" based on the seven great saints.
  • Seven Promises [Saptapadi], Seven Rounds in Hindu Wedding and Seven Reincarnation.
  • According to Hinduism, there are seven worlds in the universe, seven seas in the world and seven Rishies (seven gurus) called sapta rishis.
  • Seven hills at tirumala also known as Yedu Kondalavadu [in Telugu], ezhu malaiyan [in Tamil] means "Sevenhills God".
  • The seven virgin goddesses (or Saptha Kannimar ) are worshipped in temples in Tamil Nadu, India.
  • There are 7 Chakras in the basic model used in various eastern traditions and philosophies.


  • The number of ayat in surat al-Fatiha.
  • The number of heavens.
  • The number of hells.
  • The number of circumambulations that are made around the Kaaba.
  • The number of walks between Al-Safa and Al-Marwah pilgrims perform during the Hajj and the Umrah.
  • The number of doors to hell is seven (for heaven the number of doors is eight).
  • In Verse 12:46 (see Islamic view of Joseph) of the Quran, Joseph (Yusef) is asked to interpret the King's dream where seven fat cows were dreamt to have been devoured by seven skinny cows and seven green spikes, and others shrivelled.
  • The number of the big sins or vices is seven which are from a Hadith of the prophet Mohamed: "Avoid the seven sins polytheism, witchcraft, the killing of the soul which Allah has forbidden except by right, consuming riba, consuming the wealth of the orphan, to escape from the battles and slandering chaste women".
  • A naming ceremony is held for babies on their seventh day of life.


  • Shiv`a (another pronunciation of the Hebrew word for 7—(Hebrew: שבעה, "seven")), is the number of days of mourning. Hence, one sits Shiva. As in Shiva (Judaism).
  • The weekly Torah portion is divided into seven aliyahs, and seven Jewish men (or boys over the age of 13 who are considered men; Bar Mitzvah) are called up for the reading of these aliyahs during Shabbat morning services.
  • Seven blessings are recited under the chuppah during a Jewish wedding ceremony.
  • A Jewish bride and groom are feted with seven days of festive meals after their wedding, known as Sheva Berachot ("Seven Blessings").
  • The number of Ushpizzin (also known as the "Seven Shepherds") who visit the sukkah during the holiday of Sukkot: Abraham, Isaac, Jacob, Joseph, Moses, Aaron, and David.
  • The number of nations God told the Israelites they would displace when they entered the land of Israel (Deut. 7:1): the Hittite, the Girgashite, the Amorite, the Canaanite, the Perizzite, the Hivite, and the Jebusite.
  • In Breslov tradition, the seven orifices of the face (2 eyes, 2 nostrils, 2 ears, and the mouth) are called "The Seven Candles."
  • The 7 Sephirot of primary conscious emotion that are attributes of the creator.

Chinese Taoism

  1. Golden Star
  2. White Clouds
  3. Blue (Heaven) Sky
  4. B-lack (of Colors) Moon Empty Infinity Space / Earth (where grown Trees)
  5. Green Wood
  6. Red (Hell) Fire


  • The number of daughters of Atlas in the Pleiades (also called the "Seven Sisters").
  • The number of saints appearing in a constellation called "Saptharishi Mandalam" in Indian astronomy.


Deity, being, or character
  • The Seven Lucky Gods refer to the seven gods of good fortune in Japanese mythology.
  • The number of archangels according to some systems.
  • In Buddhism, Buddha walked 7 steps at his birth.
  • In Khasi mythology, the seven divine women who were left behind on earth and became the ancestresses of all humankind.
  • The number of sleeping men in the Christian myth of the "Seven Sleepers".
  • The number of sages in Hindu mythology; their wives are the deities referred to as the Sapta Matrka or "Seven Mothers".
  • In Iran,[18] German, Spanish, and other cultures that speak Romance Languages, cats are said to have seven lives as opposed to English, where cats are said to have nine lives.
  • In Irish mythology, the epic hero Cúchulainn is associated with the number 7. He has seven fingers on each hand, seven toes on each foot, and seven pupils in each eye. In the Irish epic Táin Bó Cúailnge, Cúchulainn is 7 years old when he receives his first weapons and defeats the armies of the Ulaidh and his son Connla is 7 years old when he is slain by Cúchulainn in "The Death of Aife's Only Son".
  • In Galician folklore, a seventh son will be a werewolf. In other folklores, after six daughters, the seventh child is to be a son and a werewolf. In other European folklores, the seventh son of a seventh son will be a child with special powers of healing and clairvoyant seeing, and in other cultures that seventh son of a seventh son would be a vampire.
  • In Guaraní mythology, the number of prominent legendary monsters.
  • In the eponymous British folk tale, Thomas the Rhymer went to live in the faerie kingdom for seven years.
  • Mahatma Gandhi's list of the destructive Seven Blunders of the World that cause violence: Wealth without work, pleasure without conscience, knowledge without character, commerce without morality, science without humanity, religion without sacrifice and politics without principle.
  • The cosmogony of Urantia[19] gives an explanation to the sacredness of the number 7 in some religions, including those based on a triple deity: 7 indeed is the number of all the possible combinations of three elements taken one by one, two by two, or by three. It therefore expresses all the associative possibilities of the three fundamental aspects of the absolute (Christian Trinity, for example, or Trimurti in Hinduism) which organizes the Creation. The seventh of these combinations being the one that combines the three aspects, 7 therefore also expresses spiritual achievement.
  • The number of main islands of mythological Atlantis.
  • The number of gateways traversed by Inanna during her descent into the underworld.
  • Cibola was one of the legendary Seven Cities of Gold the Spanish thought existed.
  • In the Bahá'í faith, the text The Seven Valleys, by the Prophet-Founder Bahá'u'lláh, relates the journey of the soul through the seven "valleys" of Search, Love, Knowledge, Unity, Contentment, Wonderment, and finally True Poverty and Absolute Nothingness.
Thing, concept, or symbol





Heptane is an alkane with 7 carbon atoms per molecule

The periodic table has 7 rows of known elements

  • The number of periods, or horizontal rows of elements, in the periodic table (as of 2016).
  • The number of principal energy levels for electrons around the nucleus.
  • The number of crystal systems: triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic.
  • The number of crystal lattice systems: cubic (or isometric), hexagonal, tetragonal, rhombohedral, orthorhombic, monoclinic and triclinic.


Isaac Newton's 7 colors of the rainbow
Isaac Newton's 7 colors of the rainbow



Temporal, seasonal and holidays

See also


  1. ^ "Sloane's A088165 : NSW primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  2. ^ "Sloane's A050918 : Woodall primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  3. ^ "Sloane's A088054 : Factorial primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  4. ^ "Sloane's A031157 : Numbers that are both lucky and prime". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  5. ^ "Sloane's A035497 : Happy primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  6. ^ "Sloane's A003173 : Heegner numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  7. ^ Bryan Bunch, The Kingdom of Infinite Number. New York: W. H. Freeman & Company (2000): 82
  8. ^ "Sloane's A003215 : Hex (or centered hexagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-01.
  9. ^ Georges Ifrah, The Universal History of Numbers: From Prehistory to the Invention of the Computer transl. David Bellos et al. London: The Harvill Press (1998): 395, Fig. 24.67
  10. ^ Eeva Törmänen (September 8, 2011). "Aamulehti: Opetushallitus harkitsee numero 7 viivan palauttamista". Tekniikka & Talous (in Finnish).
  11. ^ "Education writing numerals in grade 1." Archived 2008-10-02 at the Wayback Machine(Russian)
  12. ^ Elli Harju (August 6, 2015). ""Nenosen seiska" teki paluun: Tiesitkö, mistä poikkiviiva on peräisin?". Iltalehti (in Finnish).
  13. ^ "Μαθηματικά Α' Δημοτικού" [Mathematics for the First Grade] (PDF) (in Greek). Ministry of Education, Research, and Religions. p. 33. Retrieved May 7, 2018.
  14. ^ "Example of teaching materials for pre-schoolers"(French)
  15. ^ Mark, Joshua. "Pharaoh". Ancient History Encyclopedia. Retrieved 25 January 2017.
  16. ^ 21Then Peter came to Jesus and asked, "Lord, how many times shall I forgive my brother when he sins against me? Up to seven times?" 22Jesus answered, "I tell you, not seven times, but seventy times seven."
  17. ^ "Sermon Illustrations". Retrieved 2012-09-07.
  18. ^ "''Encyclopædia Britannica'' "Number Symbolism"". Retrieved 2012-09-07.
  19. ^ "Chapter I. The Creative Thesis of Perfection by William S. Sadler, Jr. - Urantia Book - Urantia Foundation". 17 August 2011.
  20. ^ Bellos, Alex (8 April 2014). "'Seven' triumphs in poll to discover world's favourite number". The Guardian. Retrieved 9 February 2017.
  21. ^ "Is seven your favorite number? We thought so. Here's what it says about you". Public Radio International. 2014-04-08. Retrieved 9 February 2017.
  22. ^ "SI brochure, The seven SI base units". Archived from the original on 2009-10-01. Retrieved 2009-09-11.
  23. ^ "SI brochure, SI derived units". Archived from the original on 2009-10-01. Retrieved 2009-09-11.


External links

This page was last edited on 16 June 2019, at 08:12
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.