1. Computer Science 20 Discrete Mathematics for Computer Science All the Math you need for your Computer Science courses that you won’t learn in your Math Courses 1/23/121

2. Some Topics Formal logic (p ∨ q) ∧ ¬(p ∧ q) Graphs and digraphs Probability Counting Number theory p ≡ q r (mod m) … see the “placement test” on the web site a f c d b 1/23/122

3. Skills!!! How to do proofs –By contradiction –By induction –…–… How to read and write mathematics –And typeset! How to collaborate How to present clearly and persuasively 1/23/123

4. 3 Principles of Course Philosophy 1.Learning, not competing 2.Learn by doing, not by listening 3.Many small bites 1/23/124

5. Typical Class Day Before class: –Reading and check-in problems (30-60 mins) In class –Mini-lecture (10-20 mins) –Collaborative problem solving in groups of 4 (30-40 mins) After class and before next class –Homework (60-90 mins) So class week = –3 hours class time –≤ 7.5 hours out-of-class time Most readings from MIT course notes 1/23/125

6. Requirements Attendance is mandatory! –See “Course policies” for details –Official/emergency absences ⇒ email cs20@seas.harvard.edu –Class begins at 10:10 sharp –Homework boxes removed at 10:15, no late submissions 2 hour exams 3-hour final during exam period 1/23/126

7. Tentative Grading Mix Homework35% Midterms (2)30% Final exam25% Check-in questions10% (Poor attendance: Exclusion or failure) 1/23/127

8. Support and Resources Web site –Where schedule, HWs, slides, etc. are posted TFs –See calendar on web site for office hours Volunteers Piazza (after study card day) Tool for answering check-in questions (see course home page and get an account!) Reading assignments and check-in questions are on the check-in tool 1/23/128

9. And now – the course in action! 1/23/129