CS109: Probability for Computer Scientists
Autumn 2026
Monday, Wednesday, Friday 1:30pm - 2:50pm in-person in Hewlett 200

Week 1 TODO

Enjoy the first lecture
Join the Ed forum
Read the Syllabus
Sign up for a tutorial
Start PSet 1

Teaching Team

Instructor:
Chris Gregg
Chris

OH: Fri 9-11am
CoDa E128
TAs: cs109 @ cs.stanford.edu

This Week in CS109
Date Lecture Outside Class
Wed, September 23rd Welcome / Foundations Lecture 1 LLM Learning Guide
Fri, September 25th Conditional Probability Lecture 2 LLM Learning Guide
Welcome

Welcome to CS109! We are looking forward to an uplifting and exciting quarter. Class starts Wednesday, September 23rd at 1:30pm PT in Hewlett 200. See you there 🌱.

Getting Started in CS109

The Syllabus page has details on course logistics.
The Honor Code handout describes how the Honor Code applies in the context of the work you will do in CS109.
The Schedule page has a list of all topics that we will cover in CS109, the lecture schedule, and the problem set dates and deadlines.
The Office Hours page has contact information for the teaching team. Office Hours will be listed on that calendar and start in Week 1.
This quarter we are running three-person Oxford-style tutorials instead of large sections. Tutorials begin in Week 2, and sign-up details will be announced in lecture on the first day of class. You do not enroll in a tutorial via Axess.


RESOURCES

Discussion
Course Reader
Syllabus
Schedule
Office Hours

Key Dates

Midterm: October 22nd, 6:30pm
Final: Dec 9th, 3:30pm
Last lecture: Dec 2nd

Course Values

Everyone is welcome. Intellectual joy. Be kind. Be humane. Social connection. Learn by doing. Thrill of building. Adapt to new contexts.
CS109: Probability for Comp. Science
Autumn 2026, MWF 1:30pm - 2:50pm, Hewlett 200

Week 1 TODO

Enjoy the first lecture
Join the Ed forum
Read the Syllabus
Sign up for a tutorial
Start PSet 1

Teaching Team

Instructor: Chris Gregg

RESOURCES


Key Dates

Midterm: October 22nd, 6:30pm
Final: Dec 9th, 3:30pm
Last lecture: Dec 2nd

Announcements

This Week in CS109
Date Lecture Outside Class
Wed, September 23rd Welcome / Foundations Lecture 1 LLM Learning Guide
Fri, September 25th Conditional Probability Lecture 2 LLM Learning Guide
Welcome

Welcome to CS109! We are looking forward to an uplifting and exciting quarter. Class starts Wednesday, September 23rd at 1:30pm PT in Hewlett 200. See you there 🌱.

Getting Started in CS109

The Syllabus page has details on course logistics.
The Honor Code handout describes how the Honor Code applies in the context of the work you will do in CS109.
The Schedule page has a list of all topics that we will cover in CS109, the lecture schedule, and the problem set dates and deadlines.
The Office Hours page has contact information for the teaching team. Office Hours will be listed on that calendar and start in Week 1.
This quarter we are running three-person Oxford-style tutorials instead of large sections. Tutorials begin in Week 2, and sign-up details will be announced in lecture on the first day of class. You do not enroll in a tutorial via Axess.


Course Values

Everyone is welcome. Intellectual joy. Be kind. Be humane. Social connection. Learn by doing. Thrill of building. Adapt to new contexts.