('''seven''') is the Natural Number following 6 and preceding 8 .
The SI Prefix for 10007 is Zetta (Z), and for its reciprocal Zepto (z).
- Although the ''divisible by seven (7) test'' is not well known (especially compared to the popular ''divisible by three ( 3 ) test''), there is an easy way to test if a natural number is evenly Divisible by seven (7). See also Divisibility Rule .
:# Remove the last digit,
:# Double it, and
:# Subtract it from the remaining digits.
:# If the result is negative and there are 2 or more digits, drop the negative sign.
:# Repeat until you end up with a result that is a multiple of seven (7). (i.e. -7, 0, or +7)
:For example, the number 1358 is evenly divisible by seven, since:
- 2) = 119
- 2) = -7
:Using Number Theory the proof is rather easy, once we rewrite the number in the form:
::n = 10 + '''b'''
:: is the remaining digits, and
:: is the last digit.
::10a + b = 0 (mod 7)
- (10a + b) = 0 (mod 7)
::49a + a + 5b = 0 (mod 7)
::a + 5b - 7b = 0 (mod 7)
::a - 2b = 0 (mod 7)
- A group or a series of seven is a Heptad .
- 7 is the only dimension, besides the familiar 3, in which a vector Cross Product can be defined.
In quaternary, 7 is the smallest prime with a composite sum of digits.
In the beginning, various Hindu s wrote 7 more or less in one stroke as a curve that looks like an Uppercase J upside down. 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 Arab s 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, and so they were also concerned with making their 7 more different. For the Khmer this often involved adding a horizontal line above the glyph. 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 One .
On the Seven-segment Display s of pocket calculators and digital watches, 7 is the number with the most common glyph variation (0, 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.
The reason is that 7 is written as in ① in Japan,Korea and so on.
In fonts with Text Figures , 7 usually has a descender, for example, .
- The number of spots in a common Ladybug .
- The number of objects in the Solar System visible to the naked eye, the classical " Planet s" ( Moon , Mars , Mercury , Jupiter , Venus , Saturn , Sun ). This fact is believed to have led to the concept of seven Days Of The Week .
- Messier Object M7 , a magnitude 3.5 Open Cluster in the constellation Scorpius .
- The spiral Galaxy in the Constellation Sculptor
- The seven daughters of Atlas in the Pleiades (also called the " Seven Sisters ").
- The series which began on -2590 April 8 and ended on -1310 May 16 . The duration of Saros series 7 was 1280.1 years, and it contained 72 solar eclipses.
- The Saros number of the Lunar Eclipse series which began on -2595 July 15 and ended on -1008 February 22 . The duration of Saros series 7 was 1586.6 years, and it contained 89 lunar eclipses.
- The Magical Number Seven, Plus Or Minus Two is the title of a 1956 paper by the cognitive psychologist George A. Miller which hypothesises that the effective channel capacity of human senses is equivalent to between 5 and 9 equally-weighted error-less choices.
There are several albums titled ''7'':
- A highly symbolic number in the Hebrew Bible , being, for example, the day on which God rested in Genesis
- The number of Churches Of Asia the Book of Revelation is adressed to.
- The number of nations God told the Hebrews they would displace when they came to Israel. (Deut. 7:1)"When the LORD thy God shall bring thee into the land whither thou goest to possess it, and shall cast out many nations before thee, the Hittite, and the Girgashite, and the Amorite, and the Canaanite, and the Perizzite, and the Hivite, and the Jebusite, seven nations greater and mightier than thou"
- The number of Ayat in Sura t Al-Fatiha
- The number of Heaven s in Islamic tradition
- The number of Earth s in Islamic tradition
- The numbers seven, seventy, seventy thousand, etc. are also used in Islamic traditions to denote an infinite or high number. In Arabic seventy, seventy thousand, etc. is used to mean infinite. This is because 1 is the smallest, 2 is just after 1, 5 and 10 are exact, 4 and 6 are just before and after 5, 9 is just before 10. This leaves 3, 7, and 8. 8 is closer to the end although it is larger. 8 is also an even number so divisible by 2. Between 3 and 7, 3 is smaller so 7 is chosen to represent infinite.
- The number of The Deadly Sins : lust, avarice, envy, pride, sloth, gluttony and wrath
- The seven terraces of Mount Purgatory (one per deadly sin)
- The number of Sacraments in the Roman Catholic faith
- The number of palms in an Egypt ian '' Sacred Cubit ''
- The number of heads of The Beast of the book of Revelation , and of some other monsters, like the Hydra
- The minor symbol number of Yang from the Taoist Yin-yang
- The number of times Cain will be avenged upon for the murder of his brother Abel
- The number of ranks in Mithraism
- The number of gateways traversed by Inanna during her descent into the Underworld
for 7]]
- Historical years: , 7 B.C. , or 1907
- It is traditionally thought that there are seven continents on Earth.
- Seven is the smallest positive integer requiring more than one syllable in English.
- There are seven musicians in a Septet and seven babies born in a set of Septuplet s. The most famous set of septuplets are the McCaughey Septuplets , who were born in 1997 .
is also:
- The largest number of sticks (or other cylindrical objects) that can be tied into a bundle such that the shape of the bundle remains fixed. This may have led to the number being viewed with mystical significance by ancient man.
- The number of Opening s into the human Head ( Mouth , two Eye s, two Ear s, two Nostril s).
- The number of Sphere s in the Ptolemaic System
- In Astrology , Libra is the 7th Astrological Sign of the Zodiac .
- The traditional number of Wonders Of The Ancient World .
- Viewed as a Lucky Number in many Western cultures, and in Japanese Culture .
- The number of Day s in a Week . Whether Saturday or Sunday is the seventh day varies across cultures.
- The number of the Ages Of Man into which William Shakespeare divided a lifetime
- The figurative number of Seas
- The number of colors of the Rainbow (the Asteroid 7 Iris is named after the rainbow goddess Iris )
- The number of basic principles of the Bushido
- The number of points on a Sheriff 's Star
- The average number of digits that can be stored in Short-term Memory
- In Galicia n 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 Vampire .
- When rolling two standard six-sided Dice , seven is the number most likely to occur.
- Seven is the sum of any two opposite sides on a standard six-sided die
- The number of dwarves in the movie ''Snow White''
- The number of rings given to the Dwarf Lords in J.R.R. Tolkien's '' The Lord Of The Rings ''
- The Heptarchy , from the ( Greek for ''seven realm'', is the name applied by historians to the period ( 500 - 850 AD) in English History after the Anglo-Saxon conquest of England , derived from the seven kingdoms of Northumbria , Mercia , East Anglia , Essex , Kent , Sussex , and Wessex , which eventually merged to become the Kingdom Of England during the early 10th Century .
- September was the seventh month in the ancient Roman Calendar , as its name indicates. After The Reform That Led To The Current Order , the seventh month is July.
- Septidi was the seventh day of the Decade in the French Revolutionary Calendar
- The traditional count of Basque Provinces as expressed in the slogan '' Zazpiak Bat ''
- The '' Seven Sages Of Greece '': Solon, Chilon, Thales, Bias, Cleobulus, Pittacus and Periander.
or '''7''' is all or part of a vast number of names and titles of people, artworks or organizations, including:
- Part of the names of:
- --- Aleksis Kivi 's " Seven Brothers ", the most famous book of Finnish literature
- --- '' Seven Pillars Of Wisdom '', a book written by T. E. Lawrence
- --- '' The Secret Seven '', name of children adventure book by Enid Blyton
- --- The book '' Seven Years In Tibet ''
- --- Kurosawa 's film '' The Seven Samurai '', that inspired the 1960 movie with Steve McQueen '' The Magnificent Seven '' and its own sequels
- --- Several groupings called the Seven Sisters
- --- The Seven Virgins:
-- The Seven Virgins Mountain Range in Sri Lanka , which was the scene of an Air Disaster on 4 December 1974 , involving a DC-8 Series 55F passenger jetliner operated by the charter company Martinair which left 191 dead.
-- the Saptha Kanniyar were seven faithful devotees of Siva , who give birth to seven boys, in Hindu Mythology .
-- An anonymous 17th Century Carol , ''The Seven Virgins ''.
- --- Seven Sisters, a 1998 song album by pop singer Meja
- --- Seven Of Nine , a crewmember in the Star Trek universe
- --- The World Sevens Series in Rugby Union , including the Hong Kong Sevens
- --- The Sport Itself
- --- The Seven Network of Australia
- --- '' The Seven Habits Of Highly Effective People '', a book by Stephen Covey
- --- The metal band Avenged Sevenfold , also known as A7X.
- --- ''Seven Nation Army,'' a single by the White Stripes
- 007 , Codename for James Bond , a fictional secret Spy agent
- In the InuYasha series, the Shichinintai are, as their name says, a band of seven mercenaries.
- In Fist Of The North Star ( Hokuto No Ken ), the main character, Kenshiro , is also known as "the man with seven wounds" for the seven scars on his body in the shape of the Big Dipper .
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