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The earliest attempt at designing a mechanical adding machine was probably by Leonardo da Vinci (1452-1519), according to some of his notes found in 1967 in the National Museum of Spain. The next two documented attempts were by the German Wilhelm Schickard (1592-1635) in 1623. The location or existence of the two prototypes are unknown.
In 1642, the 18 year old Frenchman, Blaise Pascal (1623-1662), invented the first "arithmetical machine", and subsequently developed it further. About 50 of these machines still exist.
