**Year 1671**

Gottfried Leibniz

Who was German mathematician made a machine to do multiplication operations was named as stepped reckoner.

This machine was capable of multiply number up to 5 and 12 digits operands. He also worked to invent calculus.

**Year 1775**

Charles Earl Stanhope

He worked to make a machine which would be able to multiply the digits. He was one of the successful to design calculator which can multiply the digits.

**Year 1776**

Matheus Hahn

He started work in year 1770 to make a multiplying calculator and make it possible in year 1776.

**Year 1786**

J.H Muller

His idea was difference engine. This calculator was very useful for calculation of values of a polynomial. Due to shortage of funds his project was not accomplished at that time.

**Year 1801**

Joseph Maire Jacuar

He invented an automatic loom that was controlled by punch cards.

**Year 1820**

Charles Thomas de Colmar

He was the first who invented the first mass produced machine called atithmometer. Its method was same as Leibniz machine to multiply but it can also do division which was the valuable addition in invention of calculation machines.

**Year 1822**

Charlas Babbage

He invented the first ever mechanical machine (computer) that was first sketch of difference engine. He invented the analytical engine that was basically a mathematical device and was difference engine to solve polynomials. The invented machine were so complicated to built the idea of Charlas babbage was likely to be implanted.

**Year 1834**

George Schetuz

He was the first man who invented a difference engine after the study of work of babbages work,

Charlas Babbage

Continue his work on analytical engine. Read Only Memory (ROM) was used to store the programs. He worked on this for 6 years and was able to a minor change in it.

**Year 1843**

Scheutz

He and his son EdvardScheutz made difference engine with printing facility and this was an innovative idea on which Swedish government was planned to fund for the further development.

**Year 1848**

George Bole

He was the first man who developed well known binary algebra called Boolean algebra. He was in nationality Greek. He was great inventor who provide beasline for development of binary computers.

**Year 1853**

Scheutzes

He was the first man who was able to complete first difference engine that was named as Tabulating Machine. The Machine worked on 15 digits numbers with printed output that was actually Babbage’s wish. A firm of London called Brain Donkin built a machine like Babbage machine later.

**Year 1858**

Frist Tabulating Machine

The fist tabulating machine was purchased by two organizations: One by Dudley Observatory in Albany and second by British government. This machine was used to generate the set of astronomical tables. The interesting is that Dudley Observatory directors was fired from his job due to excessive expenses on this creative machine.

**Year 1871**

Babbage

He worked on Analytical engines mill and printer and will designed a prototype for the analytical engine.

**Year 1878**

Roman Verea

He was the man who designed a calculator using internal multiplication table and this was faster than shifting carriage of any other digital mechanism.

**Year 1885**

Frank Stephan Baldwin

He and T. Odhner worked to build multiplying calculator which was like Atithmometer and enters into mass production. In this machine the fluted drums are swapped up by by variable-toothed gear. A disk with radial pegs was use to generate the results. They worked to enhance this machine and finally produced pinewheel calculator.