Really good professor. Knows exactly what to teach and how to teach it. Anyone talking about his accent is just being pretentious cause it isn't that bad. He's a very good professor to have for math.

Great Professor, very fluent with the material. Helpful and answers doubts in class. He has a heavy accent though but you'll get used to that in a lecture or two. All in all great, definitely recommend him

I enrolled in Castella's class because my first pass was too late and at first I was skeptical of him because of his heavy accent. Gradually, I started liking him because I actually understand what he is teaching in class as opposed to the troubles I had during 31A.

His tests are fair. The test score will reflect the amount of effort you put into it. I scored well on both his midterms. Overall, I would recommend taking him

Very good professor！His notes are quite clear and he really knows how to teach.The exams are fair.

Castella is very clear on what you should know for the tests. If you study the practice tests he provides well, you are set for the actual midterm/final! There are no curve balls! The only downside is, everyone thinks this class is easy, and if you make a silly mistake on the test, it can set you below the curve quite easily. For the second midterm, I got a hold of a past midterm and did it over and over again, and got 100% on the actual midterm. Just don't make silly mistakes and you'll be good.

Professor Castella has a very heavy accent, so most of the time I have no idea what he is saying (but since the things he write on board make sense, it's fine). Most of the examples he use in class comes from the textbook, so if you don't understand just go read the book. His homework questions are a little bit more challenging than the textbook questions, but those questions really do increase your understanding of the concepts.
I had Brown for Math 31A and I got a B because Brown is very conceptual (his tests are very challenging for me, and they look nothing like the textbook questions), however professor Castella's tests are very fair, there are no surprises and he doesn't really try to trick you. I got A on both midterms (the class average for both is around 90).

I never really did attend his lectures, but ended up with an A. He has a heavy Spanish accent. But he is unquestionably a great professor, and even better, one of the nicest professors you'll ever see. He is really friendly, is EXTREMELY prompt at responding to emails, and even nicer when you go to office hour. He's just too good a person. The tests were quite fair. Although, do not confuse them with easy. Basically if you do your work, you'll get what you deserve. Just to tell you how efficient he is at his work, he graded the entire 31B final in less than 8 hours, and even posted the final grades.
I am a HUGE fan of this guy, and he is my absolute favorite. A very pleasant person to talk to, a very nice and helpful human being, efficient at his job, and above all a great professor. Take him.
(Again, this class is not extremely easy, but at the same time, it is more than quite possible to get a great grade in his class)

To put it simply, Castella is a great math professor, and he is the best of the four I've had at UCLA. He does have a Spanish accent, but I thought he was still understandable. That aside, his notes are quite clear, and he focuses a lot on examples. He made linear algebra computational rather than focus on a lot of geometrical understanding and theorems (a huge contrast to my nightmare with Gilmore for Math 32B-good thing she's not teaching here anymore). He is fair in his exams although the midterms were time-constrained. I did well on the first midterm, but because I had an LS midterm on the day before the second midterm and due to stupid mistakes, I actually did really bad on the second exam even though it was fair in retrospect. However, his policy of dropping the lower midterm saved me, as I got 100% on the final (yes, it is doable for a math class) and I got an A+ in the class. For the exams, focus on his practice exams he gives you, as the textbook for the class was horrible. His excellent and clear notes were sufficient. On the first day of class, he seemed really serious and in a bad mood, but I learned that he just has a serious personality, so don't be scared to approach him during office hours, as he is helpful. He also assigns practice problems from the textbook, and although some were irrelevant to do looking back at the practice exams, I recommend to still do them if you have the time. His homework is not from the textbook, so my advice is to work on it with a group of friends/classmates-I did this and it helped us understand the material even more. Overall, I recommend Castella, as he is one of the most straightforward math professors you can get.

Castella is a great math professor. Very clear, helpful lectures.

The tests were challenging, largely because of the time constraint, but very comparable to the homework.