Topic: calculator

calculator or calculating machine, device for performing numerical computations; it may be mechanical, electromechanical, or electronic. The electronic computer is also a calculator but performs other functions as well. Mechanical and Electromechanical Calculators Early devices used to aid in calculation include the abacus (still common in E Asia) and the counting rods, or "bones," of the Scottish mathematician John Napier . The slide rule , invented in 1622 by William Oughtred, an English mathematician, was widely used to make approximate calculations, but it has... Read more