Brahmagupta, 630 A.D

Positive and Negative numbers and their calculations were explained first by Brahmagupta in his book Brahmasputa Siddhanta.

He presented rules for them in terms of fortunes (positive numbers) and debts (negative numbers).

Brahmagupta’s understanding of numbers exceeded that of other mathematicians of the time, and he made full use of the place system in his method of multiplication.

Brahmagupta headed the leading astronomical observatory in India and wrote two works on mathematics and astronomy. The works dealt with topics such as eclipses, risings and settings, and conjunctions of the planets with each other and with fixed stars.

Brahmagupta, 630 A.D., said, the following about Gravity, “Bodies fall towards the earth as it is in the nature of the earth to attract bodies, just as it is in the nature of water to flow".