History (Early Counting Device )

Abacus :
Invented 2000 years ago, from Egypt, Made of Wooden frame, Still used in China and other countries. Can do simple calculations
Napier's Bones :
Scottish Mathematician John Napier built, 11 Sets of Bones were used, numbers were engraved, can do multiplication
Slide Rule :
William oughtred developed, consist of two scale, can do multiply easily.
Pascal's Calculating Machine :
French Mathematician built, used for tax calculating, at Royen
Leibniz's Calculating Machine :
Gottfried Leibniz built, Can do multiple, addition, square root easily.
Analytical Engine & Differential Engine :
Built by Charles Babbage, Known as Father of Computer Science
Punched Card :
Dr. Hermanhollerith Developed, used to solve the problem in American Census.
Mark I, Mark II, (First computer ), ABC, ENIAC etc.