I was kind of freaking out because my first math midterm at UCLA I got a 70 on. One thing to blow my chem midterm because it was my weakest subject but another thing entirely to screw up a math midterm in what was by far my strongest subject. Was in a probability class taught by a guy fresh off his Ph.D from Cambridge and I guess he gave us a Cambridge level exam because turned out I had one of the highest grades in the class lol (everyone else I talked to in the class got 20-30 on it). Best teacher I ever had though was the world famous Terry Tao. The Terry Tao who was studying group theory and calculus at age 8. Nobody knew who he was back then though and he was younger than all the grad students in the class when I took a topology course from him. Yet we immediately all knew we were taking a course from an Einstein level genius and that he was 100% going to win a Fields Medal (which he did a few years later for a mindblowing result called the Green-Tao Theorem). Dude had this ability to take these crazy ideas from topology and real analysis and explain them in a way that made them seem obvious. His exams felt easy because I learned so much in his course but it was a ton of work. Still love reading his blog.
Another thing I loved about the math department at UCLA was the professors knew we were all broke as hell so a lot of the courses they'd assign textbooks that were $5 to $10.
Never heard of Tao before. You were lucky there. For some reason topology was the one math course that had me floored. I passed it but felt utterly lost. I only passed because I followed the logic, the theorems and proofs, but I was in a daze in terms of grasping where it was going and why. I figure it was because of two factors: (1) the class was huge, probably a couple hundred, maybe more and (2) I suppose the guy teaching it lacked the ability to engage his students. Oh, and I suppose the text book was no particular help in countering (1) & (2).
"Probability." I took a statistics class, upper division, I believe, maybe 101, and it was a comprehensive introduction for people comfortable with math/science and got an A. I don't remember a lot, but some basic stuff. It's a great field, of course, in spite of what Mark Twain said about statistics. He never studied it, only saw what was said in newspaper columns, I assume. I don't know the state of statistics in Twain's day, but I suppose there was some sophistication by that time.