My nephew's 10 in the 5th grade and yesterday I was helping him
  with Complex Fraction simplification and subtraction. I think he
  spent more time ranting about the unnecessary quantity of the
  homework and how Nazi like the teacher is about "show your
  work". The thing is, like you and me, he can usually just "look
  at" a math problem and know the answer. He's failed homework for
  getting the right answers and not showing his work.* I really
  wanted to go in an punch the teacher.* It'd be worth a fine and
  jail time honestly. I explained last year how his "show your
  work" is a part of the system, and how it ties into everybody
  getting paid $$$ so he understands... but still pisses him off,
  just as it did for me.. and did for you.