Arabic numerals, also called Hindu-Arabic or Indo-Arabic numerals, are the ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, based on the Hindu–Arabic numeral system, the most common system for the symbolic representation of numbers in the world today. In this system, a sequence of digits such as "975" is read as a single number, using the position of the digit in the sequence to interpret its value. The symbol for  zero is the key for the effectiveness of the system, which was developed by ancient mathematicians in the Indian Subcontinent around AD 500.