These flashcards are designed to be able to print as double sided cards, with one addition fact on the front and the related subtraction fact on the back. In this way, students can learn about the three numbers within the fact family. Eight strategies are based on adding a number to ten - remove two from the other number to add to the eight and create a ten (ex. 8+4 = 8+2+2 = 10+2 = 12). Facts go from 2+8 / 10-8 to 8+8 / 16-8.