Hes great, the other reviews go in depth so I dont have much to say except take his classes :).

TAKE HIM!!! Jukka is by far one of the best professors at UCLA. He genuinely cares for his students and offered so much material that helped. I had never had any previous calculus experience, and while sometimes the lectures confused me, him posting the slides and assigning relevant problems in the worksheet and homework really helped me get a good understanding. Also he is SO HELPFUL with getting your grade up, the homework replaced one of our midterm scores and he gave us extra credit on a midterm that he had to grade himself despite him already having this curve in place. There were so many office hours and he would always be willing to work through problems with students. I cannot stress enough how amazing he is, some may complain about the workload, but since the homework replaces the midterm, I believe doing all those problems is extremely well worth it. Overall, totally take him if you can!!!

Keranen is an amazing professor. He cares about his students' learning and makes his lectures interesting for them. His tests are fair. His grading and format for assignments is fair. Very good professor and makes 30B easy to learn.

Best professor at UCLA!

Best professor you could ever have at UCLA. He is the GOAT. professor Jukka really devote almost all of his time to his students. He explain almost every problem from the homework so you probably will receive full score for the hw. He has very thorough study guide for every tests (eg, he even marks the page number of his lecture slides that you need to know for the exam). He is very very approachable and very helpful professor. You will wish to take him again because I do.

There's a lot I could say about Jukka. You can tell he is extremely fond of and dedicated to mathematics. There are a plethora of ways he shows this. He devotes extra time to student hours, and will even have extra student hours on his weekend break. He allows a flashcard on his tests because his focus is not on memorization, it's on application and understanding. He has policies that ensure that if you put in the work, you will end up with a good grade. For example, he drops the lowest two homework and drops your lowest assessment, be it the homework, midterm 1 or midterm 2. Trust that he will find time for you and your struggles, if you fail his class, all I can say is that it is not his fault.