Mechanical Calculators
1623-1822
- Wilhelm Schickard's machine for automatic addition, subtraction, and partly multiplication in 1623
- Blaise Pascal's addition machine in 1645
- many similar efforts during 1674-1820
- Tomas de Colmar's Arithmometer, the first mass produced calculator in 1820
- Charles Babbage's Difference Engine, for solving mathematical problems including simple differential equations in 1822.