Born at Khawarizm (Kheva), south of the Aral Sea, he flourished in Baghdad from 813 to 833. He was an astronomer and geographer but is best known as a mathematician. The word algebra was derived from his book Al-Jabr wa-al-Muqabilah. He brought into mathematics the use of zero and the rest of the Indian system of numerals (now known as `Arabic numerals'), and developed the decimal system