Curta Mechanical Calculator, a small, hand-cranked mechanical calculator introduced by Curt Herzstark in 1948. It can be used to perform addition, subtraction, multiplication, division, and (with more difficulty) square roots and other operations. considered the best portable calculators available until they were displaced by electronic calculators in the 1970s.
Pascal's Calculator (1670). A mechanical calculator that could add and subtract, built by the philosopher Blaise Pascal in the 1670s. The system of cranks and gears is comparable in complexity to the Antikythera mechanism from 1000 years earlier.