You can hardly understand him and his lectures and explanations are super confusing. The discussion is very helpful for clarification on the topics. There are only two HW assignments collected and graded all quarter. The first midterm was so easy, the second was super hard, and the final was so impossible he had to give hints in the middle of the test. Only nice part was that we got cheat sheets for all the tests.

The absolute worst professor I've ever had. He refuses to pass back graded exams in class. If you want to see how well you did you have to go to office hours and pick the exam up in person. Then, he doesn't even show up to his own office hours. His lectures are also incredibly unclear! He is completely careless with his notation so if you don't already know what's going on, it can be really difficult to follow. The material itself is not that hard, but he goes over everything so quickly you don't get a chance to understand what's happening before he's already moved on. Also, he never bothers to move the blackboard up after he's done writing on it. If you're sitting in the back, you straight up don't get to see what he's writing. Homework and practice problems are poorly worded and confusing. He obviously doesn't proofread, because variable names and values will just change in the middle of the problem. If you're taking his class, going to discussion and TA office hours are a must (again, he doesn't show up to his own, so going to see him directly is not an option).

Overall, 170A with Professor Tang is pretty meh

Good things:
1. Nice curve: He gives out 30-40% A/A-, which is nice
2. Low workload: We only had 2 graded homework assignments for the whole quarter. I barely spent time on this class except for a few days before the midterm and final
3. The midterms and finals were heavily based on class examples, homework and sample exams. I didn't need the textbook at all.

Bad things:
1. As the other reviews mention, he isn't a great lecturer. He goes really fast in lecture and often skips critical steps. If you ask him to re-explain things, however, he usually does.
2. Exams were pretty difficult, with midterm averages being ~60, and the final average being ~50.
3. He isn't very helpful: In office hours, I had to wait for long times as he would often be speaking to students in a non-English language. He also rescheduled his office hours once without telling us in class.

If you're really interested in learning the material, I'd recommend someone else. But, if you want a class with a low-ish workload and are willing to spend time at TA office hours, I'd recommend taking Tang

Before midterms and final, he sent out practice midterms/final with a creepy sentence: "Be careful, the real test will be harder than this one." And it actually turned out this way.

Best professor I have ever had. He is so helpful and his tests are pretty fair. He's very generous at curving are fair!

Having took Calculus BC in high school, I wanted to take 31B as a review and to relearn series (since I hear that college math classes were very different). While I did well in high school, he managed to confuse me, from his heavy accent to his especially confusing and disorganized lectures.

Most of the class was self-study, and thankfully I found two friends in this class whom I could study with them. His actual midterms and finals were definitely harder than the practice midterm and final he handed out, so be wary when he hands those out in class, because they aren't similar. I personally did okay in the class, but I recommend to find another teacher if you can.

Having him rn in IEOR Columbia

While successfully escaped from him at UCLA, getting caught eventually.