'''Real numbers''' are numbers that can be represented by some infinite or finite [[decimal]] representation, such as 0.707106781187...

~~They are called ~~The term "realnumber" exists for historical reasons; it was once thought that such numbers " ~~because they ~~actually ~~exist as quantities in ~~" existed (hence the word "real ~~world~~"), ~~i.e. as measures, weights, temperatures. In ~~in contrast~~, ~~to the supposed non-existence of [[imaginary number]]s ~~are just an abstract concept~~. However, ~~but ~~advances in [[complex analysis]] in the 19th century revealed that imaginary numbers do ~~not exist concretely ~~, in fact, exist, and the terminology of "real ~~world~~" and "imaginary" is now understood to be just that--terminology.

In classical physics, measurements of things that can vary smoothly and continuously, like [[speed]] or [[temperature]], are treated as real numbers.