For more information on using Cooperative Learning to differentiate instruction with or without the iPad I highly recommend these resources put together by St. Clair County RESA Math and Science Assistant Director, Laura Chambless.
I've also included a few links to Cube and Thinking Dot activities and examples to help get you started.
Kagan Cooperative Learning - Learning Cubes
Cube and Thinking Dot Activities
Thinking Cube resources
Thinking Cube example