INVENTION OF MODERN COMPUTER

         (a) NAPIER's BONES-:
           An English mathematician John Napier built a mechanical device for the purpose of multiplication in 1617 AD
   The device was known as Napiers Bones

         (b) SLIDE RULE-:
               English mathematician Edmund Gunter developed the slide rule. The machine could perform operation like additional,subtration ,multiplication and division

       (c)  PASCAL'S  adding and subtratory machine-:
            Blaise Pasacal developed a machine at the age of 19 that could add and subtract, the machine consist of wheel, gear and cyl;inder