Gary's Student,

I have encountered 2 problems:

First, B1 has to equal something, so instead of nothing, can we
reformulate to make B1=0?

Second, I'm getting the message "Ambiguous name detected:
Worksheet_Change". does this have anything to do with the fact that
I have a different macro on the same worksheet labeled "Private Sub
Worksheet_Change(ByVal TargetCell As Range)", which is slightly
different from yours (you don't have "Cell" shown?

Michael