Before Muslim era, Roman numerals were prevalent in the world which were difficult to understand and to remember. During Muslim era, Arabic numerals (decimal system) were introduced which are now know all over the world but few people know that these are Arabic numerals. If this had not been done mathematics would have remained primitive and there may have been no computers today. Seing the comparison among Roman and Arabic numerals below one can easily understand what I mean.
Abu Abdullah Muhammad ibn Musa al-Khwarizmi (Khwarizm, now Khiva) (Algorizm) (770 – 840 C.E) was the first to define numeric values based on number positions. He developed the system of symbolic expressions using the nine known decimal numbers and introduced zero, a numeral of fundamental importance, leading up to the so-called arithmetic of positions and the decimal system, and thus became the founder of the present computing system