Cards consist of 36 triangles with a missing angle. Students try to figure out the missing angle. This is a great way to get the entire class involved in the learning process, what most would call cooperative learning. If you are unfamiliar with the Kagan strategy of Quiz, Quiz, Trade, I will give you a brief rundown. Each student is given a card with a problem on the front and answer on the back. When the teacher gives the signal, students put their hands up and walk around until they match