Subtraction flash cards for -0 facts through -10 facts. Subtracting double facts also included.. I like to print all of the alike facts (for example all of the minus one facts) on one color. As they master them, they go into a special "fact bag". Then they get the next group of facts on another color paper to add to their fact bag. Eventually, they have a bag full of subtraction flashcards they have mastered and feel confident about! I use the bag for a lot of activities in my math block!