Roshan Tara Higher Secondary School Kashmore - #javed Willhelm Schickard invented the "Calculating Clock", the first mechanical calculator. It used a version of Napier's bones for multiplication with a mechanical adding/subtracting calculator
The sketch of one of the first calculating machines from 1632 made by Wilhelm Schickard, a university professor from Tuebingen. The model of the machine that turned out to be functional was
Wilhelm Schickard and the Rotating Clock (Complete History) - History-Computer
Calculating clock” by Schickard - Baron von Freytag-Löringhoff — Google Arts & Culture
The History Of The Calculator: When was the Calculator First Invented?
Replica Of Schickards Calculating Clock Photograph by Science Source - Pixels
File:Schickard Calculator replica at CHM.jpg - Wikimedia Commons