Plickers allows you to use your iPhone or Android device to check for understanding on the fly in the class and recording the responses. So, how does it work? Run Plickers, sign up for the free account and create your classes. When you've done that, create questions and link those to your classes. You will need to print a class set of cards for the class and assign a card number to a particular student. I do this by chair number. When you are ready, give out the cards and ask the kids a question. The cards have an A, B, C, and D side. The kids hold up the card with the correct answer (Letter) on top and the teacher opens the question and scans the classroom with the phone. The app records the A, B, C, D answer from the students and the teacher can instantly see who did and didn't answer and who was correct and incorrect. This provides for quick check for understanding and records the responses for the teacher (for participation points, exit/entrance tickets, and more.)
I hope I described this sufficiently in this short post. Cool App. I totally recommend it!