Learning and practicing subtraction facts can be hard for some students. Throw away the worksheets and teach your child how to subtract using a Ziplock bag with a sliding lock. First, use a Sharpee marker to write out a number line at the top of the bag. Then, put a white piece of paper in the bag so the numbers will be easier to see. Next, buy or make a set of subtraction flashcards. Finally, show the cards to your student and if they can’t answer the problem right away, let them slide the lock to find the answer.