Aryabhata, decimals and zero

In 499 the twenty-three-year-old Aryabhata completes the Aryabhatiya — a brief versified compendium of mathematics and astronomy. He gives a good approximation of pi, a table of sines and rules for solving equations, explains day and night by the rotation of the earth, and eclipses by shadow rather than by a mythical dragon. In his time India is already developing the writing of numbers with nine signs and positional value, and soon zero is recognised as a number in its own right, fit for calculation. Through the Arab scholars this reckoning will come to Europe and become the everyday arithmetic of the whole world.