Two early counting devices were the abacus and the Antikythera mechanism. The abacus and similar counting devices were in use across many nations and cultures. The Antikythera mechanism hails from the Greek island of Antikythera.
Early evidence of abaci dates to 200 B.C. in China. The classic abacus consists of a number of rows of sliding beads on a frame with a horizontal beam dividing the frame into two unequal halves. The number of rows vary, but there are typically five beads below the beam and two above. An abacus is capable of performing addition, subtraction, multiplication, division, cube root and square root, and it is a much faster method of mathematics than writing calculations by hand. In fact, some parts of rural China still employ abaci in businesses, as electricity frequently fails and renders modern counting devices useless.
Over a century ago an unusual mechanism was found off the coast of the Greek island of Antikythera. It was thought to perhaps be an astrolabe or atomic clock, but its true use was unknown. It was called the Antikythera mechanism, and it has been extensively studied ever since. World class technology industries, such as Hewlett Packard, have worked on the mechanism. It is now understood to track various cycles of the solar system, and it operates as a sort of mechanical computer. The Antikythera mechanism is still under investigation and is considered to be the most complex piece of machinery from the ancient world.