7 (number)

"Seven" redirects here. For other uses, see Seven (disambiguation).
6 7 8
−1 0 1 2 3 4 5 6 7 8 9
Cardinal seven
Ordinal 7th
(seventh)
Numeral system septenary
Factorization prime
Prime 4th
Divisors 1, 7
Roman numeral VII
Roman numeral (unicode) Ⅶ, ⅶ
Greek prefix hepta-/hept-
Latin prefix septua-
Binary 1112
Ternary 213
Quaternary 134
Quinary 125
Senary 116
Octal 78
Duodecimal 712
Hexadecimal 716
Vigesimal 720
Base 36 736
Greek numeral Z, ζ
Amharic
Arabic & Kurdish ٧
Persian ٧
Urdu ۷
Bengali
Chinese numeral 七(qi)
Devanāgarī (sat)
Telugu
Tamil
Hebrew ז (Zayin)
Khmer
Thai
Saraiki ٧

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

Mathematics

In fact, if one sorts the digits in the number 142857 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

Numeral systems

Base Numeral system
2 binary 111
3 ternary 21
4 quaternary 13
5 quinary 12
6 senary 11
7 septenary 10
over 7 (octal, decimal, etc.) 7

In quaternary, 7 is the smallest prime with a composite sum of digits.

Basic calculations

Multiplication 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 50 100 1000
7 × x 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140 147 154 161 168 175 350 700 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 11 12 13
7x 7 49 343 2401 16807 117649 823543 5764801 40353607 282475249 1977326743 13841287201 96889010407
x7 1 128 2187 16384 78125 279936 823543 2097152 4782969 10000000 19487171 35831808 62748517
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-look-alike into an uppercase V-look-alike. 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.

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 and Korea, 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 increasingly in the UK 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 these can appear similar when written in certain styles of handwriting. This glyph is used in official handwriting rules for primary school in Russia, Ukraine, Poland, other Slavic countries,[11] as well as in France, Belgium, Finland,[12] Romania, Germany and Hungary.[13]

Automotive and transportation

Classical world

Classical antiquity

Commerce and business

Food and beverages

Media and entertainment

Film

Characters

Titles

Films

Games

Video games

Literature

Music

Sports

Baseball
Football and soccer
Frisbee and Ultimate Frisbee
Handball
Motor sports
Rugby
Rugby league
  • The jersey number 7 is worn by the starting scrum-half/halfback in most competitions (but not in the European Super League, which uses static squad numbering).
  • 7, The number of consecutive State of Origin Series wins (2006-2012) by Queensland against New South Wales in Australia. The highest since the inception of the State of Origin Series concept which commenced in 1980.
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.)
  • A converted try is worth 7 points. This number is also significant because the standard bonus points system used in most competitions awards 1 bonus point to a team that loses by 7 points or less.
  • The IRB Sevens World Series, an annual competition for national teams in rugby union sevens (see below)
  • The Rugby World Cup Sevens, the World Cup for the union version of Sevens
Cross-code
  • Rugby sevens, a variant of union and league that contains only seven players per side instead of the standard 15 (union) or 13 (league)
Softball
Track and field
Water polo

Television

Networks and stations

Programs

Places

Religion and mythology

Old Testament

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:

New Testament

Other sevens in Christian knowledge and practice include:

Hinduism

Islam

Judaism

Astrology

Others

Deity, being, or character
Place
Scripture
Thing, concept, or symbol
Time

Science

Astronomy

Biology

Chemistry

Physics

Isaac Newton's 7 colors of the rainbow

Psychology

Software

Temporal, seasonal and holidays

See also

Notes

  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."(Russian)
  12. Elli Harju (August 6, 2015). ""Nenosen seiska" teki paluun: Tiesitkö, mistä poikkiviiva on peräisin?". Iltalehti (in Finnish).
  13. "Example of teaching materials for pre-schoolers"(French)
  14. 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.'
  15. "Sermon Illustrations". Bible.org. Retrieved 2012-09-07.
  16. "''Encyclopædia Britannica'' "Number Symbolism"". Britannica.com. Retrieved 2012-09-07.
  17. Urantia Fondation website
  18. Nunitus, Septem (2016). 777: Messages from the Elder Gods (777 Series Book 1). Elder Gods Press. p. 5. ASIN B01I0EUQGA
  19. "SI brochure, The seven SI base units". Retrieved 2009-09-11.
  20. "SI brochure, SI derived units". Retrieved 2009-09-11.

References

External links

Wikimedia Commons has media related to 7 (number).
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