Fall 2018 - The only bad thing about his lecture is he spends too much time at the easy stuff (before midterm 1) and goes super fast afterward for the difficult topics. His class is pretty clear and involves much proof rather than calculation, but the homework is extremely challenging. You should expect to see the homework requires as hard proof as he teaches on lectures. Fortunately, only calculation parts of homework are graded and the exams consist mainly of calculations. EDIT: After the final, I changed Overall score from 4 to 2. The final exam is not difficult in terms of analyzing and prooving, but it involved INSANE numbers in 3 of 8 questions, each requiring 4-digit multiplying 4-digit for about 30 times. I actually finished the equations 80 minutes ahead of time, but still couldn't finish the calculations by the end of exam. Apparently, he did not do a single step to solve the questions after making the exam paper, or he would have discovered how absurd are the numbers he gave.