Abacus: the Chinese Calculating Board
From the Greek word "ABAX", meaning "calculating board" or "calculating table". Invented by the Chinese, the first record of the abacus was from a sketch of one in a book from the Yuan Dynasty (14th Century). It's Mandarin name is "Suan Pan" which means "caculating plate". It's inventor is unknown, but the abacus is often referred to as the "first computer" because it was used as a mathematic model for early electronic computers.
The abacus can be used to ADD, SUBTRACT, MULTIPLY, and DIVIDE as well as work with sophisticated mathematical problems such as fractions and square root.
In Asian countries it is not unusual to see shopkeepers and street vendors using an abacus to calculate invoices, especially where electricity is not convenient. Some elderly residents actually prefer the abacus over newer electronic devices. The calculations made on an abacus are immediate, with the device retaining the results in "visual storage" much like a computer display. All one has to do is read off the answer. Some say that since it has a better "keyboard" than the Western calculators, an abacus is actually faster when working with large amounts of numbers.
While Westerners are used to seeing "miniature" abacus models in gift shops, usually made of brass, the preferred models are larger (around 14" wide), with frame and beads made of good quality, well-seasoned wood.