Mechanical calculator
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A mechanical calculator, or calculating machine, is a mechanical device used to perform the basic operations of arithmetic automatically, or a simulation like an analog computer or a slide rule. Most
Four of Pascal's calculators and one machine built by Lépine in 1725, Musée des Arts et Métiers
Replica of Schickard´s calculator
Detail of a replica of an 18th-century calculating machine, designed and built by German Johann-Helfrich Müller.
A mechanical calculator from Anton Braun, dated 1727
Slide rule
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A slide rule is a hand-operated mechanical calculator consisting of slidable rulers for conducting mathematical operations such as multiplication, division, exponents, roots, logarithms, and trigonome
Mechanical calculator
…calculating machine, is a mechanical device used to perform the basic operations of arithmetic automatically, or a simulation like an analog computer or a slide rule. Most mechanical calculators were comparable in size to small desktop computers and have been rendered obsolete by the advent of the electronic calculator…
Typical ten-inch (25 cm) student slide rule (Pickett N902-T simplex trig)
Cursor on a slide rule
This slide rule is positioned to yield several values: From C scale to D scale (multiply by 2), from D scale to C scale (divide by 2), A and B scales (multiply and divide by 4), A and D scales (squares and square roots).
A normal-sized slide rule sitting inside a 7-foot (2.1 m) teaching model