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# 8 (number)

(Redirected from 8th)
 Cardinal 8 eight Ordinal 8th eighth Numeral system octal Factorization 23 Divisors 1, 2, 4, 8 Roman numeral VIII Unicode representation of Roman numeral Ⅷ, ⅷ prefixes octa-/oct- (from Greek) octo-/oct- (from Latin) Binary 1000 Octal 10 Duodecimal 8 Hexadecimal 8 Hebrew ח (Het)

8 (eight) is the natural number following 7 and preceding 9.

The SI prefix for 10008 is yotta (Y), and for its reciprocal yocto (y).

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## Evolution of the glyph

In the beginning, various groups in India wrote 8 more or less in one stroke as a curve that looks like an uppercase H with the bottom half of the left line and the upper half of the right line removed. At one point this glyph came close to looking like our modern 5. With the western Ghubar Arabs, the similarity of the glyph to 5 was banished by connecting the beginning and the end of stroke together, and it was only a matter of the Europeans rounding the glyph that led to our modern 8.

## In mathematics

It is a composite number, its proper divisors being 1, 2, and 4. Eight is a power of two, being 23, or two cubed.

8 is the base of the octal number system, which is mostly used with computers. In octal, one digit represents three bits.

The number 8 is a Fibonacci number, being 3 plus 5. The next Fibonacci number is 13.

In binary code eight is 1000; in ternary code eight is 22; in quaternary numeral system code eight is 20; in quinary eight is 13; in senary eight is 12; in septenary eight is 11; in octal eight is 10; in novenary code and all codes above (such as decimal and hexadecimal) eight is 8. In Roman numerals eight is VIII.

A polygon with eight sides is an octagon. Figurate numbers representing octagons (including eight) are called octagonal numbers. A polyhedron with eight faces is an octahedron.

Sphenic numbers always have exactly eight divisors.

## In science

In astronomy,

Messier object M8, a magnitude 5.0 nebula in the constellation Sagittarius.
The New General Catalogue object NGC 8 , a double star in the constellation Pegasus
The Saros number of the solar eclipse series which began on -2579 March 7 and ended on -1281 April 26. The duration of Saros series 8 was 1298.1 years, and it contained 73 solar eclipses.
The Saros number of the lunar eclipse series which began on -2512 July 27 and ended on -961 February 13. The duration of Saros series 7 was 1550.6 years, and it contained 87 lunar eclipses.

## In other fields

Last updated: 06-04-2005 02:45:52
03-10-2013 05:06:04