Category:Numbers - All About All

Category:Numbers

A number is an abstract entity used to describe quantity. There are lots of numbers. The most familiar numbers are the natural numbers {0, 1, 2, ...} used for counting and denoted by N. If the negative whole numbers are included, one obtains the integers Z. Ratios of integers are called rational numbers or vulgar fractions; the set of all rational numbers is denoted by Q. If all infinite and non-repeating decimal expansions are included, one obtains the real numbers R. Those real numbers which are not rational are called irrational numbers. The real numbers are in turn extended to the complex numbers C in order to be able to solve all algebraic equations. The above symbols are often written in blackboard bold, thus:

See also

• WikiProject Numbers
• Category:Integers — containing the articles titled 1 (number), 2 (number), and so on

Subcategories

Articles in category "Numbers"