My son uses Math Academy. My son has a folder of paper that's printed on one side and destined for the recycle bin. He uses when he can't solve the problems in

My son uses Math Academy. My son has a folder of paper that's printed on one side and destined for the recycle bin. He uses when he can't solve the problems in his head. I don't see any good reason to retain this stuff: - his progress is tracked in Math Academy - he doesn't need a reference sheet, as anything he needs to reference is stuff he will memorize using Math Academy or Anki