Information provided by the grader:

HW1:
I give every question 3 points, and the total is 15 points.
For the first two questions about induction, I deducted one point
if the student did not write down the assumption in the induction step
and specify what is k in the proving.

HW2:
Question 1 (3 points): you have to prove "if" AND "only if" parts.
Question 2 (2 points): do not forget the combinations with 1, e.g. 1 and 2,
1 and 3, 1 and 4
Question 3 (3 points):
Question 4 (3 points)
Question 5 (2 points)
Question 6 (2 points)

HW3:
No comment on the homework this week, since everyone did a good job.

HW4:
For question number 1, there are four pairs of integers. Points are
deducted if you only wrote one pair. For question umber 3, you have to find
all the solutions if there are. For question number 5, please specify what
is k or n in the induction.

HW5:
For question number 2, as long as your theory is reasonable, you got some
points For the last two questions, most students found all the possible
solutions.

HW7:
I give 4 points to the first three questions, and 3 points to the last question.

HW8:
I gave three points to each question. Most students got above 12 points overall.
One point was deducted if the proving is oversimplified.

HW10:
I assigned 2 points per question for 7.1.2e, 7.2.1g and 7.2.6e.
and assigned 3 points per question for 7.1.22, 7.1.32 and 7.2.12.

HW11:
I gave 4 points for question 7.2.12, 7.2.34, and 7.4.23,
and 3 points for question 7.4.14.