Set of 10 symbols 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 that represent numbers in the decimal number system. They originated in India in the 6th or 7th century and were introduced to Europe through Arab mathematicians around the 12th century (see al-Khwarizmi). They represented a profound break with previous methods of counting, such as the abacus, and paved the way for the development of algebra