Materials: wooden frame and plastic beads. Approximate dimensions: 24.5 x 7.6 x 1.9 cm. Chinese wooden abacus - 13 stems. Practical and educational. Instructions not included. To learn to count and to perform basic mathematical operations such as: addition, subtraction, multiplication, division. Strong and very durable. Product The abacus is a calculating tool, invented in between 1000 BC. AD and 500 BC. It often has a wooden frame and rods on which beads slide. This is a very old calculation tool, which was used by traders and financial advisers. Owning an abacus was a sign of great wealth. The abacus is still used today - most notably in the financial world. Display this awesome abacus on your desk to increase your business luck. It is also very useful for small traders. The abacus is a very practical tool for learning to count and teaching mathematics. It is practical and educational - an indispensable tool for teachers and students alike. "