a desk calculator that performs arithmetic operations. A machine for arithmetic calculations was devised by B. Pascal in 1641; however, the first practical machine that performed four arithmetic operations was constructed by the German clock master Han in 1790. In 1890 the St. Petersburg mechanic V. T. Odner set up the production of Russian calculators which served as the prototype of subsequent arithmometer models.

The arithmometer is provided with a mechanism for setting and transferring numbers to a counter, a revolution counter, a result register, a unit for clearing results, and manual or electric drives. The arithmometer is most effective for performing multiplication and division. With the development of computer technology, arithmometers have been replaced by the more perfected keyboard computers.