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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).

  3. 2,147,483,647 - Wikipedia

    en.wikipedia.org/wiki/2,147,483,647

    Euler ascertained that 2 31 − 1 = 2147483647 is a prime number; and this is the greatest at present known to be such, and, consequently, the last of the above perfect numbers [i.e., 2 30 (2 31 − 1)], which depends upon this, is the greatest perfect number known at present, and probably the greatest that ever will be discovered; for as they ...

  4. Billion - Wikipedia

    en.wikipedia.org/wiki/Billion

    Billion is a word for a large number, and it has two distinct definitions: 1,000,000,000 , i.e. one thousand million , or 10 9 (ten to the ninth power ), as defined on the short scale . This is now the most common sense of the word in all varieties of English; it has long been established in American English and has since become common in ...

  5. Order of magnitude - Wikipedia

    en.wikipedia.org/wiki/Order_of_magnitude

    For example, 1 and 1.02 are within an order of magnitude. So are 1 and 2, 1 and 9, or 1 and 0.2. However, 1 and 15 are not within an order of magnitude, since their ratio is 15/1 = 15 > 10. The reciprocal ratio, 1/15, is less than 0.1, so the same result is obtained.

  6. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    In statistics, the 68–95–99.7 rule, also known as the empirical rule, and sometimes abbreviated 3sr, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution: approximately 68%, 95%, and 99.7% of the values lie within one, two, and three standard deviations of the mean, respectively.

  7. Long and short scales - Wikipedia

    en.wikipedia.org/wiki/Long_and_short_scales

    Each of these words translates to the American English or post-1974 British English word billion (10 9 in the short scale). The term billion originally meant 10 12 when introduced. [7] In long scale countries, milliard was defined to its current value of 10 9, leaving billion at its original 10 12 value and so on for the larger numbers. [7]

  8. 1,000,000,000 - Wikipedia

    en.wikipedia.org/wiki/1,000,000,000

    This is an accepted version of this page This is the latest accepted revision, reviewed on 20 January 2025. See also: Orders of magnitude (numbers) and Long and short scales Natural number 1000000000 List of numbers Integers ← 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 Cardinal One billion (short scale) One thousand million, or one milliard (long scale) Ordinal One billionth (short ...

  9. Names of large numbers - Wikipedia

    en.wikipedia.org/wiki/Names_of_large_numbers

    1 1 10 6: Million Million Million M Mega-2 1 10 9: Billion Thousand million Milliard G Giga-3 2 10 12: Trillion Billion Billion T Tera-4 2 10 15: Quadrillion Thousand billion Billiard P Peta-5 3 10 18: Quintillion Trillion Trillion E Exa-6 3 10 21: Sextillion Thousand trillion Trilliard Z Zetta-7 4 10 24: Septillion Quadrillion Quadrillion Y ...