# Number

A number is a mathematical object used to count, label, and measure. In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational numbers, irrational numbers, and complex numbers.

Mathematical operations are certain procedures that take one or more numbers as input and produce a number as output. Unary operations take a single input number and produce a single output number. For example, the successor operation adds one to an integer, thus the successor of 4 is 5. Binary operations take two input numbers and produce a single output number. Examples of binary operations include addition, subtraction, multiplication, division, and exponentiation. The study of numerical operations is called arithmetic.

A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (telephone numbers), for ordering (serial numbers), and for codes (e.g., ISBNs).

In common use, the word number can mean the abstract object, the symbol, or the word for the number.

### Other articles related to "number, numbers":

39 (number) - In Other Fields
... "'39" does in fact fall in the thirty-ninth position The retired jersey number of former baseball player Roy Campanella The book series "The 39 Clues" revolves around 39 clues hidden around the world ... History The number of signers to the United States Constitution, out of 55 members of the Philadelphia Convention delegates The traditional number of times ... slang for "thank you" when written with numbers (3=san 9=kyu) Pier 39 in San Francisco The number of the French department Jura In Afghanistan, the number 39 is considered unlucky, due to the belief ...
39 (number) - In Mathematics
39 is the smallest natural number which has three partitions into three parts which all give the same product when multiplied {25, 8, 6}, {24, 10, 5}, {20, 15, 4} ... The thirteenth Perrin number is 39, which comes after 17, 22, 29 (it is the sum of the first two mentioned) ... is obviously more than 39 twice, 39 is a Størmer number ...
38 (number)
... This article discusses the number thirty-eight. 38, see 38 (disambiguation) ← 39 ... → 38 ← 39 ... → List of numbers — Integers 90 ... → Cardinal thirty-eight Ordinal 38th (thirty-eighth) Factorization ...
Natural Logarithm - Origin of The Term natural Logarithm
... But mathematically, the number 10 is not particularly significant ... the basis for many societies’ numbering systems—likely arises from humans’ typical number of fingers ... As an example, there are a number of simple series involving the natural logarithm ...
496 (number) - In Mathematics
496 is most notable for being a perfect number, and one of the earliest numbers to be recognized as such ... As a perfect number, it is tied to the Mersenne prime 31, 25 - 1, with 24 ( 25 - 1 ) yielding 496 ... Also related to its being a perfect number, 496 is a harmonic divisor number, since the number of proper divisors of 496 divided by the sum of the reciprocals of its divisors, 1, 2, 4, 8, 16, 31, 62, 124, 248 and ...

### Famous quotes containing the word number:

In the multitude of middle-aged men who go about their vocations in a daily course determined for them much in the same way as the tie of their cravats, there is always a good number who once meant to shape their own deeds and alter the world a little.
George Eliot [Mary Ann (or Marian)

Mining today is an affair of mathematics, of finance, of the latest in engineering skill. Cautious men behind polished desks in San Francisco figure out in advance the amount of metal to a cubic yard, the number of yards washed a day, the cost of each operation. They have no need of grubstakes.
Merle Colby, U.S. public relief program (1935-1943)

The growing good of the world is partly dependent on unhistoric acts; and that things are not so ill with you and me as they might have been, is half owing to the number who lived faithfully a hidden life, and rest in unvisited tombs.
George Eliot [Mary Ann (or Marian)