Slide rules are very limited computers though. They mostly let you do fairly rapid multiplication and division up to limited precision. Also look up trig values and logs (obviously). Probably a few other things depending on the model and its scales.

But really the only thing it buys you is some speed over just pen and paper. (At least assuming you have trig, log, and probably some other tables from a standard math handbook. Which could presumably be derived in a manner I don't recall off the top of my head but likely very painfully.)