The abacus is a counting frame used since ancient times as a calculating device. The word abacus is derived from the Greek word "abax" meaning "flat surface."
An abacus is made up of rods and beads within a wooden frame. The abacus is a counting board, which is simply a board onto which small pebbles are placed. Counting boards have been found to date back to 300 B.C. Evidence of the first abacuses dates to ancient Rome. These early versions were small enough to fit in the hand. Abacuses are still widely used across Asia and Africa by merchants and traders.