Great lecturer and he is good at explaining things in office hours too. Reasonable tests and homework, class work is fairly straightforward and easy in general, just go to extra hours and talk to him and the TA and the class will be even easier!

Reasonable tests and homework. Easy, but not so easy it feels pointless. Very straightforward and clear lectures. Wants his students to learn. Lots of help during office hours. Definitely take him, you will learn a lot without much stress.

Best math professor

He could work on explaining the algorithms we learn in this class to make them easier to work with, but he's very aware of this & you can tell he tries really hard to be as clear as he can. Funny guy, very lenient grader here since this class was mainly algorithms. As long as he saw you were using them right, you'd get most credit. 10/10 very fair.

Karel is good professor but he could be more engaging to the class, it seems like he's talking to himself when lecturing which can cause him to go fast and miss important details. Other than that he's helpful in office hours(he's a little awkward sometimes) and tests are pretty fair just know your definitions inside and out.

Math 117 is like Math 8 on steroids. It's challenging, but Karel is more than aware of this and tries to make this class manageable. He's knowledgeable and his lectures are relatively organized. Difficult exams, however he gives extra credit and preps you with similar exam questions. He's really friendly guy and easy on the eyes. I recommend him.

He is disorganized... But he gives out great scores on a class that used to be hard... And he is a kind teacher...

His lectures were very clear and very structured. Some of the homeworks were a little confusing but not impossible like other profs. He answers questions very well, and definitely wants you to understand the material.

Casteels is an awesome professor. His lectures were always very clear and structured. His problem sets were extremely fun to complete; he never failed to provide interesting questions. The final included computing R(3,4), and he broke the proof into manageable parts. UCSB will miss him!

He is a good professor.He can explain the theorem clearly. He gave some challenging question as the homework. At first, I think he is a boring guy but after a quarter, I think his class is interesting.

Really, really, enjoyed the honors seminar with Karel. The man knows his stuff and offered a great intro to pure and advanced mathematics. Don't expect integrals or derivatives in this truly engaging math class. Thanks prof!

Awesome professor, explain things very clearly. Willing to help if you aren't afraid of asking. Tests are very reasonable, i really recommend this professor. Had him for Math 3A,3B, 3Honor and will be taking his Math 5 Honor in winter.

He's a pretty cool professor, slightly awkward sometimes, but tests are reasonable and he's much more clear in office hours.

Casteels is a great professor. Very thorough explanations. Gives PLENTY of help if you're not afraid to ask. Useful in office hours AND by using the "email professor" button on webwork. Receieved an A- in his class. Tells it like it is and with effort, you'll get a solid grade. I reccommend as a math major :)

Casteels is the best college math profesor I have had so far. He is new, but he is an excellent teacher. Great clarity in explaining concepts, and he is very approachable if you ever have doubts. Go to lecture, do your homework, study 1-2 hours for exams, and the class is an easy A. I had him for both Math 3A and 3B, aced both classes.

Professor Casteels is a great math professor.

Professor Casteels is a cool guy. He is clear in teaching and is fair. He speaks English fine, unlike a lot of Math teachers at UCSB I heard don't. Math 5C is very difficult. Do his homework and study it for tests as well as study old tests for the final. He is clear in what he will put on tests, and don't be afraid to look in the book for help.

Professor Casteels is by far the best math teacher I have ever had. He is very clear and helpful, his test are fair and he only test on the material he goes over in class. Attend lecture, work hard, do the homework and you will get an A. I enjoyed his class so much that I am going to be taking his class again during the winter quarter.