Classification of Numbers
See also: List of types of numbersDifferent types of numbers are used in many cases. Numbers can be classified into sets, called number systems. (For different methods of expressing numbers with symbols, such as the Roman numerals, see numeral systems.)
| Natural | 0, 1, 2, 3, 4, ... or 1, 2, 3, 4, ... | |
|---|---|---|
| Integers | ..., −5, −4, −3, −2, −1, 0, 1, 2, 3, 4, 5, ... | |
| Rational | a⁄b where a and b are integers and b is not zero | |
| Real | The limit of a convergent sequence of rational numbers | |
| Complex | a + bi where a and b are real numbers and i is the square root of −1 |
Read more about this topic: Number
Famous quotes containing the word numbers:
“The barriers of conventionality have been raised so high, and so strangely cemented by long existence, that the only hope of overthrowing them exists in the union of numbers linked together by common opinion and effort ... the united watchword of thousands would strike at the foundation of the false system and annihilate it.”
—Mme. Ellen Louise Demorest 1824–1898, U.S. women’s magazine editor and woman’s club movement pioneer. Demorest’s Illustrated Monthly and Mirror of Fashions, p. 203 (January 1870)