Blaise Pascal (Clermont-Ferrand, 1623 – Paris, 1662) designs and builds between 1642 and 1645 the Pascaline to assist his father with tax collection in Rouen. The device adds and subtracts numbers of up to eight digits using toothed wheels with automatic carry by weight. Pascal built at least 20 prototypes before reaching a functional design; seven examples survive today in European museums. It is the first mechanical calculator produced in more than one copy and the first with a documented attempt at commercialization (Royal Privilege, 1649). It preceded Schickard in public knowledge for centuries because Pascal published his results while Schickard's letters remained archived.