The Hindu–Arabic numeral system or Hindu numeral system, a positional decimal numeral system, is the most common system for the symbolic representation of numbers in the world. It was invented between the 1st and 4th centuries by Indian mathematicians. The system was adopted by Persian mathematicians (Muḥammad ibn Mūsā al-Khwārizmī's c. 825 book On the Calculation with Hindu Numerals) and Arab mathematicians (Al-Kindi's c. 830 volumes On the Use of the Hindu Numerals) by the 9th century. It later spread to medieval Europe by the High Middle Ages.