I have a spread sheet that is laid out in sections grouped by dates. I am
trying to create a function that will sum a particular column correctly and
expand even when new information is added and the dates are resorted.

Example: Cell C100 should sum the column A80:A99, but when new information
is added and then the spread sheet is resorted the column will expand to
A80:A100 in which case Cell C101 would then properly total A80:A100 and Cell
C100 would go back to being blank.

I think there may be a way to count between blank cells and on my
spreadsheet Cell A79 will always be blank, and whatever cell in the A column
of the same row as my C cell with my formula (ie. A100 or A101) will always
be blank.

If anyone has any ideas your help would be greatly appreciated.
Thank you.