Hindu-Arabic Numerals

The Hindu-Arabic numeral system. was invented between the 1^st and 4^th centuries by Indian mathematicians. It is a positional system whose base is 10. Its introduction of the zero as a placeholder was a real breakthrough in mathematics. The system was adopted in Arabic mathematics by the 9^th century. Influential were the books of Muḥammad ibn Mūsā al-Khwārizmī (On the Calculation with Hindu Numerals, c. 825) and Al-Kindi (On the Use of the Hindu Numerals, c. 830).