First, you need to be able to solve the problem
and get the correct answer.
In order to do that, you don't ask your dog for the answer,
and you don't take a nap and dream it, and you don't sprinkle
magic dust on the paper and make the answer appear.
You do some figuring, and some calculating, and some
reasoning. THAT's your work ! Whatever you do to
find the answer, write it down next to the answer.
That's what's called 'showing your work'.