Abacus

A Simple Device Which Is Among The First Computing Instruments. Consists Of A Wooden Board Over Which U Shaped Wires Are Mounted So That The Arms Of Wires Are On Both Sides Of Board. Each Wire Has 20 Beads (10 Each Of Two Colours), Which Assists In Counting And Calculations. Available In Different Configurations (Number Of Rows Of Wire) . (4 Rows)