Hi,

I have several applications where I keep monthly data on tabbed worksheets,
labled Jan07, Feb07, Mar07... I also add a worksheet I usually call RangeEnd
that acts to stop sums for ranges.  It has been my practice to make a year
end worksheet that would have the same shape data structure and place in each
cell the formula "=sum(Jan07:RangeEnd!A1)" and copy it into all the
appropriate cells for which I want summed data.  This seems to work just fine
so long as the sells I am summing are not themselves sums.  

For example, if cell C1 holds a value, say 10.  The C1 cell in the summary
worksheet contains the sum of all the C1 cells.  If cell c3 = c3*b3, the
summary sheet correctly contains the sum of all the C3 cells.  However, if C5
for example holds =sum(C1:C4), the value I find in the summary worksheet for
C5 is 0 (zero).  

I wonder if anyone else has seen this, has a correction for it, or an
explaination why it occurs.

I appreciate your help.

Bill