Not very hard material, but kind of dry. Xiaohui mostly only reads through the lecture slides which are as lengthy as chapters in the books. But she is a really nice person, and if you have questions for her, she explains them thoroughly. The best strategy, I think, is read the text book on your own and go to office hours instead of lectures. There is a huge curve for final grade. So don't panic if you didn't do well in the first exam. But if you can, try to get at least an 8 (out of 10) in your weekly homework. Then you'll almost certainly get above a B.