Discussion sections (or "sections" for short) play an important role in making you a master of probability for computer science. Each section is headed by a section leader, who doubles as one of the awesome CAs for CS109.

Note: For the Spring 2020 quarter, our form will ask you to list some available times so that we can schedule accordingly, but we will also survey whether you anticipate section will be part of your learning environment this quarter. We realize that some of you may not be able to regularly attend discussion section, and we will provide the opportunity to substitute your section grade for a CS109 contest submission. More details on the contest to be provided mid-quarter.


Signups for sections will go out on Wednesday, April 8 (Week 1) and will be open until Saturday, April 11 (signup form: here). We will let you know which section you are in by Monday, April 13 (Week 2), and you will have your first section a few days later (during Week 2).

If you do not receive a section assignment email at the beginning of Week 2 (or if the time you were assigned no longer works for you), you need to fill out the Section Swaps and Late Signups form which is open until Tuesday, April 14, 11:59 PM Pacific (Week 2). The people who fill out that form will be notified of their new section time by Tuesday night at the latest.

For any other signup questions, you should email Cooper Raterink, Head TA, who will try to manage your assignment.

Absences and Makeups

Everyone gets two (2) unexcused section absences for the quarter. You can take this absence at any point without notifying your section leader. If you do not use your absences, your lowest section grade will be dropped.

If you cannot make your own section in a given week, you should go to the staff page and pick out a section that works for you (times are listed below each CA profile picture). You should email your section leader and the leader of the section you will be attending in advance. Note that you do not need to receive permission to attend a different section. The email just serves as notification/documentation for the section leaders. Furthermore, it is your responsibility to make sure that the CA whose section you go knows what section you came from and takes down your attendance accordingly.

Everyone can attend two (2) makeup sections with no penalty. However, in order to prevent people from abusing the makeup section policy, we will reduce your section grade for every makeup section you attend after the first two. That being said, if you want to attend extra sections just for fun (i.e., in addition to your regular section), it will not negatively impact your grade (you should still email in advance).


Your section grade makes up 5% of your overall course grade. Your section grade takes both attendance and participation into account.