CS70: Discrete Mathematics and Probability Theory, Fall 2015

Note: Please refer to Piazza post @1375 regarding RRR week section location changes.


Lecture: MWF 1:00-2:00 PM, Wheeler Auditorium

Jean Walrand
email: walrand at berkeley (.) edu
Office: 257 Cory Hall.
Office hours:
M 2:30-3:30.
W 2:30-3:30.

Satish Rao
email: satishr at cs (.) berkeley (.) edu
Office: 687 Soda Hall.
Office hours:
M 2:30-3:30.
Th 2:00-3:00.


Please see the GSI/uGSI page for information about your Student Instructors.
Please see the Reader/Tutor page for information about your Readers.


There is no textbook for this class. Instead, there is a set of fairly comprehensive lecture notes. The notes are undergoing revisions this semester, so notes posted well in advance of lecture may change closer to the date. So make sure you revisit the notes after lecture. Note 0 is background material that you should make sure you understand before the first lecture. Each note may be covered in one or more lectures.


On Calcentral! The first lecture appears to be up!


Slides follow the notes, but I do try to pull out what I garner from my own close reading, re-reading, and re-reading (and occasional edit) of the notes to both prepare lectures and these slides.


Week 1 No Discussion.
Week 2 2A;/Sol 2B;/Sol
Week 3   3B;/Sol
Week 4 4A;/Sol 4B;/Sol
Week 5 Midterm 1 5B;/Sol
Week 6 6A;/Sol 6B;/Sol
Week 7 7A;/Sol 7B;/Sol
Week 8 8A;/Sol 8B;/Sol
Week 9 Midterm 2 9B;/Sol
Week 10 10A;/Sol 10B;/Sol
Week 11 11A;/Sol 11B;/Sol
Week 12 12A;/Sol 12B;/Sol
Week 13 Midterm 3 13B;/Sol
Week 14 14A;/Sol  
Week 15 15A;/Sol 15B;/Sol


Midterm 1 Monday (Sep 21) 8:00-9:30pm
Midterm 2 Monday (Oct 19) 7:00-8:30pm
Midterm 3 Monday (Nov 16) 7:00-8:30pm
Final Tuesday (Dec 15) 11:30-2:30pm


HW Problem Due Date HW Solution
Homework 14 NA
Homework 13 Dec 2 (Wed) 10:00 PM
Homework 12 Nov 18 (Wed) 10:00 PM
Homework 11 Nov 11 (Wed) 10:00 PM
Homework 10 Nov 04 (Wed) 10:00 PM
Homework 9 Oct 28 (Wed) 10:00 PM
Homework 8 Jan 26 (Mon) 12:00 PM
Homework 7 Oct 14 (Wed) 10:00 PM
Homework 6 Oct 7 (Wed) 10:00 PM
Homework 5 Sep 30 (Wed) 10:00 PM
Homework 4 Sep 23 (Wed) 10:00 PM
Homework 3 Sep 16 (Wed) 10:00 PM
Homework 2 Sep 9 (Wed) 10:00 PM
Homework 1 Sep 2 (Wed) 10:00 PM

Homework Party/Office Hour Times


We are allowing students the choice of how to best approach the class and have designed an assessment method for each approach.

You make the choice of how you wish proceed and to be assessed on bcourses after getting feedback on the first homework.

For all options, you are encouraged to access the course resources that are available to you all; help in hw parties, office hours that will be additionally staffed by readers, discussions, and piazza.

At that point, the die is cast and you cannot change your choice.

The Sundry item below is simply some questionaires which should take roughly half an hour. All options require them.

Test only Option.

Homework Option.

Oral Quiz w/Tutor Option.

Th last option needs a bit of explaining. After each homework solution is out, each student in this category should read and understand the solutions to the homework, and then should meet with a oral quiz tutor who will test whether you understand the homework material. She or he will either check you off, or help you understand more, and ask you to try again either at that point, or after you go back and try to understand better on your own. The expectation is that the tutor option grade is 100\%.


These three configurations correspond to the European test at the end approach, the standard American approach where we force students to do homework to keep up, and the last moves toward checking in personally which has support in the education literature. To be sure, this is a brief summary of the thinking behind this.

There are clear arguments for each approach, and it is difficult for us to know what will produce the best results for students. This is an endeavor to let you choose.

Regardless of which option you choose, the course staff will support you: put together relevant homeworks for practice, along with solutions, have sections, with section worksheets, and solutions, homework parties, office hours with additional support beyond the teaching assistants, and some tutoring support.

The Curve.

We designed the curving methodology to be such you should choose the option that best fits your preferences on how to learn the material and how to organize your time.

Still, you may visit piazza to understand the curve. My feeling is that one question on a midterm or final makes more of a difference to your grade than the specifics of the curve, so your energy is better spent on making sure your learn the material.



Don't fall behind! In a conceptual class such as this, it is particularly important to maintain a steady effort throughout the semester, rather than hope to cram just before homework deadlines or exams. This is because it takes time and practice for the ideas to sink in. Make sure you allocate a sufficient number of hours every week to the class, including enough time for reading and understanding the material as well as for doing assignments. (As a rough guide, you should expect to do at least one hour of reading and two hours of problem solving for each hour of lecture.) Even though this class does not have any major projects, you should plan to spend as much time on it as on any of your other technical classes.

Take the homeworks seriously! The homeworks are explicitly designed to help you to learn the material as you go along. Although the numerical weight of the homeworks is not huge or is zero, we work hard to make them instructive and interesting. Do read the sample solutions, even for the problems on which your recieved full points. You may well learn a different way of looking at the problem, and you may also benefit from emulating the style of the solutions. (In science people learn a lot from emulating the approach of more experienced scientists.)

Don't wait until the last minute to start homeworks! Our best advice is to read through the homework problems as soon as they are available, and let them percolate in your brain. Think through possible approaches while you are waiting in line, or stuck in an elevator, or whatever. Sleeping on a problem has often helped people to come up with a creative approach to it. Definitely do not wait until the night before it is due to start working on the homework.

Make use of office hours! The instructor and TAs hold office hours expressly to help you. It is often surprising how many students do not take advantage of this service. You are free to attend as many office hours as you wish (you are not constrained just to use the office hours of your section TA). You will also likely get more out of an office hour if you have spent a little time in advance thinking about the questions you have, and formulating them precisely. (In fact, this process can often lead you to a solution yourself!)

Come to homework parties! We encourage collaboration on homeworks (but please read the homework policy above! all solutions must be your own). If you want to find a group to work with, or you and your friends want a nice place to work together, come to the homework parties.

Take part in discussion sections! Discussion sections are not auxiliary lectures. They are an opportunity for interactive learning, through guided group problem solving and other activities. The success of a discussion section depends largely on the willingness of students to participate actively in it. As with office hours, the better prepared you are for the discussion, the more you are likely to get out of it.

Form study groups! As stated above, you are encouraged to form small groups (two to four people) to work together on homeworks and on understanding the class material on a regular basis. In addition to being fun, this can save you a lot of time by generating ideas quickly and preventing you from getting hung up on some point or other. Of course, it is your responsibility to ensure that you contribute actively to the group; passive listening will likely not help you much. And recall the caveat above that you must write up your solutions on your own.

Pay attention in lectures! As the semester proceeds, many of you will no doubt feel the urge to "daydream" during lectures, or to skip them altogether, on the grounds that you can catch up by reading the lecture notes. If you follow this strategy, you should be aware that reading mathematics is NOT the same as reading a novel or a news article: each page of mathematics needs to be read many times before it is fully understood, and needs to be backed up by examples and discussion. Following the material in class should save you several readings; even just watching it go by without fully understanding it makes your later reading easier. And you also get the benefit of student questions, examples etc. Exactly how you handle lectures is up to you. One strategy is to print out the lecture notes in advance, bring them to lecture, and add a few additional notes during class.