Quote Originally Posted by snb View Post
I agree

Code:
Sub M_snb()
  [C9:F10] = [if(C9:F10<>"",if(I9:L10<>"",int((C9:F10+I9:L10)/2),C9:F10),I9:L10)]
End Sub
The only problem I have with your submission is the use of those square brackets... they are slower than using Range and Evaluate (not really noticeably so in this particular instance though) and, more importantly, they are totally inflexible... you can't concatenate variables into them so they are only usable when you know for sure your ranges are totally locked down and will never change (which I do not think will be the case for the OP's ultimate use).