Computers use algorithms to do everything from adding up a column of figures to resizing a window. Computers use algorithms to do everything from adding up a column of figures to resizing a window. Algorithms were around for a very long time before the public paid them any notice. The word itself is derived from the name of a 9th-century Persian mathematician, and the notion is simple enough: an algorithm is just any step-by-step procedure for accomplishing some task, from making the morning coffee to performing cardiac surgery. Computers use algorithms for pretty much everything they do -- adding up a column of figures, resizing a window, saving a file to disk.