Professor Zhang or "Tom," is a great professor. The course is very different from normal math classes. If you take it with Tom, he likes to do a little more than what the course requires but his extra topics are very interesting.

The basics to proofs.

Pros: Knows his stuff, tests are fair, and extremely understanding (the kind of Prof that will cancel his lectures before Thanksgiving). Cons: Accent is heavy but totally understandable though.

Read the textbook "How to Prove It" by Daniel J. Velleman.