What Are the Major Mathematical Achievements in Ancient India?

Hindu numerals are so easy and simple and so profound that we teach numbers 1, 2, 3 first before we teach alphabet to a child. They came up with a number system where they used place value notations. For zero, which is among the top 100 inventions by the American Association for the Advancement of Science, R.E.L.A.S. has mentioned that this is an approximate value because we cannot get an exact value.