Brahmagupta (7th Century AD) was a brilliant Indian mathematician and astronomer born in Bhillamala. He became head of the astronomical observatory at Ujjain, a major centre for mathematics.
His most famous work is the Brāhmasphuṭasiddhānta, a foundational text in the history of mathematics. He established the rules for operating with zero as a number and he defined the use of positive and negative numbers (fortunes and debts) in arithmetic. His work laid the essential mathematical groundwork for many later developments in the fields of both algebra and computation.