Abacus

This is a Chinese Abacus. It was introduced in China around 500 B.C. The general design of the classical abacus consists of an oblong wooden frame that is divided into two parts. Within the two parts there are generally 13 rods with five wooden beads in the bottom compartment, each bead is worth one. In the top compartment, there are two beads each worth five. The beads are considered counted when they are moved toward the top of the middle beam. The operator can perform addition, subtraction, multiplication and even some division.