Pascal's Calculator (jan 1, 1642 – dec 30, 1645)
Description:
Blaise Pascal invented a mechanical calculator in 1642. It took him3 years of work and over 50 prototypes. He was a teenager at the time.The machine worked similarly to Schickard's, by breaking multiplication into addition and subtraction. However, Pascal's machine used a different mechanism that could carry without jamming. Of the 20 "Pascalines" he made over the next ten years, nine are still working today.
https://en.wikipedia.org/wiki/Pascal%27s_calculator
Added to timeline:
Date:
jan 1, 1642
dec 30, 1645
~ 3 years and 11 months