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Improve your grade on Exam #2.

You can earn additional points towards your Exam #2 grade by completing the following assignment.

Due Thursday, 11/7.  Choose TWO problems from Exam #2 (Hint: choose the two problems that you did worst on).  Re-do these problems.  Hand in all the following, STAPLED TOGETHER, on Thursday 11/7:

  1. For each of the two problems:
    1. Clearly state how many points you received on each problem.
    2. Give an explanation consisting of at least one complete sentence explaining your error, and how you fixed it.
    3. Give a complete, correct solution to the problem.
  2. Hand in your exam paper along with your corrections.

You will be able to earn up to half the points you missed on the two selected problems, to be added back into your Exam #2 score.

Example.  Suppose you received 68 on the exam.  You choose problem #3 (scored 8 points out of 20), and problem #5 (scored 4 points out of 20).  You complete the assignment perfectly.  Since you missed a total of 28 points on these two problems (12 on problem 3, and 16 on problem 5), you will have 14 points added to your exam score.

Office hours today

I will be available between 2pm Р3pm today in my office N707.  My usual office hours (11:15-1:15) are canceled.


Prof. Reitz

IMPORTANT – Bring Written Work Chp 4-5 to class on Thursday

Hi everyone,

If you picked up your (graded) written work from Chapters 4 and 5 today, please bring it with you on Thursday to class — I need to record your score in my gradesheet, or you will not get credit for the assignment. ¬†Oops!


Prof. Reitz

Exam 2 Review UPDATE

Hi everyone,

Two things about the review sheet:

1. ¬†There is a typo in problem #5c — it should read |X|=3, instead of |A|=3.

2. As I told a number of you in my office today, I will NOT put a problem like #12 (There is no largest prime number) on the exam.

Best of luck with your studying,

Mr. Reitz

Office hours Tuesday 1-2 by request

Hi everyone,

If you have questions for me BEFORE the exam on Thursday, I can be available tomorrow (Tuesday) between 1 and 2 pm, BUT only if you notify me ahead of time (by email, or by leaving a comment here, or by telling me in class tomorrow).

Best of luck with your studying,
Prof. Reitz

Exam Review 2 UPDATE – review of division and remainders

Hi everyone,

First, the answer key for the Exam 2 review is now complete (it follows the questions in the Review document).  Second, you will notice that there are a few places (especially in problems 8 and 12) that I use basic facts about remainders when one number is divided by another.  These are facts that you understand intuitively from working with dividing numbers, but it might help to have them stated explicitly.  This is the basic fact about dividing and remainders:

Fact (The Division Algorithm).  Given two integers a and b with b>0, there exist unique integers q and r for which a=qb+r and 0\leq r <b.

What does this mean?  It expresses the fact that when we divide one integer a by another integer b, and it will go in some number of times q with a remainder of r.  The remainder r must be less than the number b that we are dividing by.  If the remainder is zero, then b divides a (because r=0 means a=qb), and if the remainder is not zero, then b does not divide a.

If you have any questions, feel free to leave a comment here.  Best of luck with your studying!

-Prof. Reitz

Exam 2 Review is posted

Find it on the “Exam Reviews” page (link in the menu above the shark). ¬†Answers to the review will be added to the document sometime this week. ¬†If you have any questions or notice any errors please let me know.

-Prof. Reitz

Office hours tomorrow (Thursday 10/10)

Hi everyone,

My office hours tomorrow will not be at the regularly scheduled time, but instead:

  • 9:00am – 10:00am (before class), in N707 – moving to the classroom around 9:45.
  • 1:45pm-2:30pm, in N707

As always, I’m happy to make individual arrangements to meet at other times – just send me an email.

Take care,
Prof. Reitz

Followup on Today’s Lecture (Tues 10/8)

Hi everyone,

In the homework from today, the final two problems (#15, 16) use an idea called “Proof by cases” (considering different possible situations within your proof). ¬† ¬†To complete these two problems, read Page 96 (starting with “4.4 Cases” and ending at the end of the first proof, at the bottom of the page). ¬†Bring your questions on Thursday!


-Prof. Reitz

Office hours today (10/4): 12pm-1pm

Hi everyone,

Office hours today will be from 12pm-1pm (I will also be able to answer a quick question or two right after class).

-Prof. Reitz