leibnitz's calculator is simply an improvised version of the adding machine. this machine could perform multiplication and division as well. ( multiplication through repeated addition and division through repeated subtraction). talking about the history of this machine it was invented by a German mathematician Gottfried Leibnitz. It used a stepped cylinder with nine teeth for varying lengths instead of wheels used by pascal.
For a better idea refer to a picture of Leibnitz's calculator:
http://images.Google.co.in/images?hl=en&q=leibnitz%27s+calculator&btnG=Search+Images&gbv=2&aq=f&oq=
(please press ctrl and then click on the above link to view the picture.) tell me if the link does not work.
who invented the first mechanical digital calculator
he is a famous maths matitian, he of course, made calculus cos he's just cool eh8)
The first calculator is believed to have been invented in North Africa, however China invented the spoon and the compass.
The introduction of the 1st mechanical calculator was invented in Europe. This type of calculator production then spread world wide. The first ever was invented by Willhelm Schickard.
The first adding calculator machine was invented by Blaise Pascal.
The first calculator was invented in 1623.
Japan ;)
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The first modern-style electronic calculator was invented in the 1960s. The first counting device, an abacus, was invented in Egypt in about 2000 BCE. The mechanical calculator was developed in the 17th century.
calculator and human computers used them.
Pascal,a great French Scientist invented the calculator.
Blaise Pascal