Print double-sided on card stock for traditional flash cards.
I use these cards when a student needs extra help with a certain set of facts. I combine the addition and subtractions cards for each number (+9s and -9s.) This is especially good if a student is stuck on a certain addition/subtraction set. One thing I like to do is to have the student find the fact families, i.e 1+9 =10; 9+1=10; 10-9=1