In math, I pretty much always need a reference. Professors don't seem to like explaining every property of things, particularly when it should have been explain

In math, I pretty much always need a reference. Professors don't seem to like explaining every property of things, particularly when it should have been explained previously. I used my phone continuously to look things up. That professor hated me. My personal preference is working through proofs and problems on my own and being able to pause lectures. Sure it takes an extra 30 minutes, but it saves hours of time later when I don't understand what I'm doing.