Estimating what you need on the final exam to earn the grade you want:

1.    Determine what grade you want (not letter grade, but numerical grade, for example, 80)

2.   Subtract the "Total points" value (last column in gradebook) from your target numerical grade (which you determined in step #1).

3.    Divide the calculated value from step #2 by 0.15.  The result is the final exam grade you need to earn the grade you want (note:  if the grade you need is greater than 100, you cannot earn the final grade that you desire)

Example:  A student wants a 90 as a final course grade.  Her lecture point total is 54.  Step #2:  90 - 54 = 36.  Step #3:  36/0.15 = 240   This student needs to earn an 240% on the final exam to guarantee a final grade of A (which is impossible).  If this student earns 100% on the final exam, her final course grade would be 69% (and although it's not a 70%, I would assign a grade of C, for doing so well on the final exam!)