Brahmagupta ( Devanagari: ब्रह्मगुप्त; * 598, † 668 ) was an Indian mathematician and astronomer. He headed the astronomical observatory at Ujjain and wrote in this feature two works on mathematics and astronomy, the Brahmasphutasiddhanta in the year 628 and the Khandakhadyaka in 665

The Brahmasphutasiddhanta is the earliest known text in which the mathematically complete zero is treated as a written number. Previously had been the Babylonians the value zero is used in the 6th century BC as a space. In addition, Brahmagupta presented in this work on rules for arithmetic with negative numbers and with the number 0, which largely correspond to already our modern understanding. The biggest difference was that Brahmagupta also the division by 0 is allowed, while in modern mathematics quotients are not defined by the divisor 0.

His best-known results include two named after him theorems about quadrilaterals tendons. The set of Brahmagupta that describes a page halving in certain tendons four corners, and the formula of Brahmagupta that calculates the area of ​​any quadrilateral tendon. On him the Brahmagupta identity goes back.