Invent (Score 2, Insightful)

Well, some did anyway. For example, in the early 1820's, when dealing with solving partial differential equations arising from heat conduction, Joseph Fourier came up with the foundations of Fourier Analysis, which has become an essential tool in a great deal of mathematics, science, and engineering. Where would we be today if he could just plug it into MATLAB and get an approximate numerical solution?

Also, although I do not really know how he did it, I belive that Euler had calculated e to 7+ decimal places in the mid 1700s.