Why was the computer invented?
Computers were made to do the very tedious computations of everyday life and business. The first calculators performed computations in seconds that would take someone using a slide rule minutes if not hours to do. Calculations for NASA entry and exit trajectories would take days or even weeks to calculate by hand and the first mainframe computers would do the calculations in minutes.
first of all they were not trying to invent computer. actully they were trying to make a machine that can calculate statics of soliders in world war I. story of first computer ENIAC