Hindu-Arabic numerals (or simply "Arabic numerals") are the standard numbers used in most of the world. They are named this way because they were first introduced by the Hindu people of India, then came by way of the Arabs (who added the important concept of zero) to the western world, where it supplanted earlier number systems such as Roman numerals.
Confusingly, the "Arabic" numbers used by the western world are different in appearance from the forms used in Arabic-speaking countries, though the basic system is the same. It is a particular point of confusion that the Arabic-script digit "5" looks like a zero to Westerners. Similarly, there are different forms of the numerals in use in India.