I use these cards in my classroom to practice many things from place value, greater than less than, putting numbers in order, etc...I cut them out, and then mounted them onto construction paper. To keep them for a long time, I laminated them. I've had the same set of cards for over 6 years now. I printed multiple sets, and put each set on a different color of construction paper so I could break the class into smaller groups to do the same thing.
Use these cards around the room as a fun way to do addition problems. I recommend mounting them on construction paper, then laminating them to have for a long time. I would place them around the room either on the floor or on tables and my students would rotate around the room completing the problems in their notebook.