The "Chinese abacus is a simple device for performing mathematical calculations. Known as the Fifth Invention of Ancient China, the abacus can perform addition, subtraction, division and multiplication; it can also be used to obtain square roots and cubic roots." chineseculture.org
The abacus is not an ancient Chinese invention. It was invented during China's middle ages, during the Ming Dynasty (1368-1644). But it's fun to use, so we included it for you.