In 770, an Indian scholar brought two highly important mathematical works to Baghdad eg Brahmasiddhanta (Sindhind to Arabs) by the great 7th century Indian mathematician Brahmagupta a mathematician and astronomer which contained early ideas of algebra.
The second manuscript contained a revolutionary system of denoting number and the concept of zero. In the 9th century, Muslim Muhammad ibn Musa al-Khwarizmi took this work, combined it with Greek geometry (The Greek contribution in science, medicine, philosophy is huge), to become what we call today as algebra.
Indian numerals were used by al-Khwarizmi in algorithms (a Latinized version of his name) to solve certain mathematical problems. Hence Muslims may have contributed but they certainly did not discover either zero or algebra and our so-called Arabic Numerals are actually Indian (Hindu) Numerals.(Khan p 202)
In Brahmaguptas Khandakhadyaka (Arkanda), Arabs first became acquainted with a scientific system of astronomy in the 8th century. Books of medicine, toxicology, philosophy, chemistry and more were also taken into the Islamic world and translated.
Indian mathematics became wide spread. Even a Spanish Muslim (11th century) praised the Indians for their superior knowledge in astronomy, mathematics, medicine, pharmacology, chemistry... .(Khan p 203-4). (Note Mayans also developed zero long before Islam entered the world!)
