How can you prevent group-work in a math exam? The reality is, there's a few "twists" (non-intuitive steps) in every proof. If you know the "twists" it cuts th

How can you prevent group-work in a math exam? The reality is, there's a few "twists" (non-intuitive steps) in every proof. If you know the "twists" it cuts the time down to 1/10th. If you're working in a group, there's a clear advantage, but no way to prove anyone cheated (unless students are dumb enough to copy it out line by line).