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.

Read more about Number: Classification of Numbers, Numerals

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

**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 citizens of Ancient Rome hit their slaves when beating them ... Internet chat 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 ...

**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 ...

**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 ... 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**...

*natural Logarithm*

... But mathematically, the

**number**10 is not particularly significant ... numbering systems—likely arises from humans’ typical

**number**of fingers ... As an example, there are a

**number**of simple series involving the natural logarithm ...

**number**)

... This article discusses the

**number**thirty-eight. 38 ← 39 ... → List of

**numbers**— Integers 90 ... → Cardinal thirty-eight Ordinal 38th (thirty-eighth ...

### Famous quotes containing the word number:

“I think, for the rest of my life, I shall refrain from looking up things. It is the most ravenous time-snatcher I know. You pull one book from the shelf, which carries a hint or a reference that sends you posthaste to another book, and that to successive others. It is incredible, the *number* of books you hopefully open and disappointedly close, only to take down another with the same result.”

—Carolyn Wells (1862–1942)

“In proportion as our inward life fails, we go more constantly and desperately to the post office. You may depend on it, that the poor fellow who walks away with the greatest *number* of letters, proud of his extensive correspondence, has not heard from himself this long while.”

—Henry David Thoreau (1817–1862)

“The two great points of difference between a democracy and a republic are: first, the delegation of the government, in the latter, to a small *number* of citizens elected by the rest; secondly, the greater *number* of citizens and greater sphere of country over which the latter may be extended.”

—James Madison (1751–1836)