Grading principles:

Problem 1: 
  -5 points each 
  
Problem 2: (15 each)
  -dividing the wrong way around -2
  -not keeping * precedence -2
  -loosing DX at the multiplication -2
  -overwriting AX and loosing data -2
  -not preparing DX = 0 for division -2
  
Problem 3: (20 each)
  -not iterating correctly -5 (-2 small error)
  -not iterating at all -10
  -not doing the operation -5
  -not initializing with 1 or the first element for the multiplication -2
  -not addressing correctly in the array -5