When I was writing accounting software, one of the areas I had to foresee was dividing by zero. The Windows core routines will 'throw an exception' when encountering a divide-by-zero. The software program must 'catch' the 'thrown exception' and handle it in some way. I wrote elaborate error functions to catch every error we could think of, but of course, some user would always manage within 30 seconds to do something stupid. However, almost all modern software handles divide-by-zero problems gracefully.
That pretty much nails it.