1 ч 35 мин, 19 окт 300 г. до нашей эры - Abacus

Описание:

The abacus is one of the earliest calculating devices ever to be made. Designed by the Babylonians in 300 B.C an Abacuses can be used to perform addition, subtraction, division and multiplication. Using this device, an individual was able to extract square-roots and cubic roots through the manipulation of beads with either the index finger or the thumb of one hand. Each abacus has a series of vertical rods running vertically across the object's frame acquaintanced by little wooden beads sliding freely and vertically around the rod. Abacuses were used predominately by flock herders to count sheep, and merchants to calculate the quantity of items they still have in inventory to sell.