Up to this point, students have not used the card game to think about integer addition; they have only created integers by finding round differentials and game To use the card game to develop integer addition, we aim for students to see that they could determine the current game differential by adding the current round differential differentials. to the previous game differential. This is a shift in how students have been calculating the current game differential-they have been calculating the current game differential by finding the difference between their total score and their partner's total score. To make the transition to integer addition, we give the whole class a problem to discuss where they can no longer find the current game differential using the method they had been using.