Ever dreamt of solving math problems in your head with the speed of a calculator? Mental math might seem challenging, but ...

The abacus is one of many counting devices invented in ancient times to help count large numbers, but it is believed that the abacus was first used by the Babylonians as early as 2,400 B.C.

The abacus has taken many forms over the centuries. In Medieval and Renaissance Europe, merchants commonly did calculating by moving wooden or metal counters along lines drawn on a wooden table known ...