First figure your homework grade.  Your HW percentage is your total 
number of HW points divided by the number of HW points which are possible.  
If I have counted correctly, there are 500 possible HW points for the 
entire semester.  However, we will figure the final HW percentage out of 
only 425 points.  You can't get more than 100% though, so once you have 
425 points you don't need to submit any more HW (although hopefully you
will find the process of submission and feedback to be good practice for
the tests).

     As an example, say you have earned 374 HW points for the semester.
Your HW percentage would be:

             374/425  = 88.0%

HW is worth 8 points overall, so you would have earned 7.04 HW points
(i.e. 88.0% of 8).

     Now figure your PRS grade.  There are about 100 PRS questions 
for the semester, so a total of 300 PRS points are possible.  However,
we will figure the final PRS percentage out of only 250 points.  Once
again, you can't get more than 100%.  Say you have earned 210 PRS points
for the semester.  Your PRS percentage would be 210/250 = 84.0%.  PRS
is worth 5 points overall, so your PRS points for the semester are 4.20
(84% of 5).

     OK, now figure your quiz grade.  We grade quizzes out of 10 points
and we take your best 10 of 13 quizzes.  Say your best 10 quizzes total 
up to 82 points.  Quizzes are worth 7 points overall so your quiz points 
for the semester are 5.74 (82% of 7).

     Now figure your test total.  Take your best 3 tests and average
them, then divide by 125 since each test is worth 125 points.  For 
example, say your test grades are 108, 91, 85, and 95.  Your test average 
is then

     (108+91+95)/3 = 98.0 divided by 125 to yield 78.4%

Now multiply by .6 since the Tests are worth 60 points overall.

     78.4 times 0.6 = 47.04

     OK, now you have your pre-exam total.

                 HW      7.04
                 PRS     4.20
                 QUIZ    5.74
                 TEST   47.04

                total   64.02

The pre-exam maximum is 80 points, so your pre-exam percentage is

           64.02/80 = 80.0%

     Will you be able to get an A?  That depends on what the final
grade scale is.  I start with no curve.  That is 

                 90 and above           A
                 80-90                  B
                 70-80                  C
                 60-70                  D
                 below 60               E

If the class average is 75 or higher, there is no change.  If the
class average falls below 75, I feel obliged to relax this scale
somewhat.  Look at 

                111 Fall 2003 web page , or
                111 Spring 1997 web page , or
                111 Spring 1996 web page 

to get an idea for what this year's scale might be.  I will make 
a guess at the final grade scale during the week before the exam, 
but the true final grade scale ultimately depends on overall class 
exam performance.

     Let's get back to our example.  You have 64.02 points going in
to the exam.  The exam is worth 20 so the best you can do is 84.02,
not enough to get an A if the class average is 75 or higher.  On
the other hand, you need at least 15.98 points from the exam to insure
yourself of a B.  The exam consists of 40 multiple choice questions,
so you need to get at least (15.98/20)*40 right, or 32 out of 40, to
absolutely insure yourself of a B.