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Nines (notation)
Nines are an informal, logarithmic notation for proportions very near to one, or equivalently percentages very near 100%. Their common uses include grading the purity of materials. Put simply, "nines" are the number of consecutive nines in a percentage such as 99% (two nines) or a decimal fraction such as 0.999 (three nines). The number of nines of a proportion is \mathrm = -\log_(1-x) However, there are different conventions for stating a non-integer number of nines. 99.5% could be expressed as "two nines five" or 2.3 nines, as outlined below. A completely pure material ( = 1) would have an infinite number of nines. Precious metals The exact purity of very fine precious metals such as platinum, gold and silver can be of great interest. Based on the system of millesimal fineness, a metal is said to be ''one nine'' or ''one nine fine'' if it is 900 fine, or 90% pure. A metal that is 990 fine is then described as ''two nines fine'' and one that is 999 fine is described as ''three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four Nines Fine Gold
4 (four) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is tetraphobia, considered unlucky in many East Asian cultures. In mathematics Four is the smallest composite number, its proper divisors being and . Four is the sum and product of two with itself: 2 + 2 = 4 = 2 x 2, the only number b such that a + a = b = a x a, which also makes four the smallest squared prime number p^. In Knuth's up-arrow notation, , and so forth, for any number of up arrows. By consequence, four is the only square one more than a prime number, specifically 3, three. The sum of the first four prime numbers 2, two + 3, three + 5, five + 7, seven is the only sum of four consecutive prime numbers that yields an Parity (mathematics), odd prime number, 17 (number), seventeen, which is the fourth super-prime. Four lies between the first proper pair of twin primes, 3, three and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
