Continued fraction

A continued fraction is a concept from mathematics and number theory. It is written as an integer, plus a fraction. The numerator of the fraction, is again an integer, and for the denominator, the rule repeats. Every real number can be expressed as a continued fraction. While it is possible to use continued fractions for calculations, they are used to find approximations for irrational numbers. 
Leonhard Euler and Joseph-Louis Lagrange first formalized the concept, even though it was used before.