I am summing a column of 5 numbers (ex. =SUM(D1:D5)) and the formula returns
zero. The formatting is number, when I try to add D1+D2+D3... and I get the
same result, zero. When I highlight the cells the Sum number on the bottom
right border gives the correct answer. Also, if I a sum formula and go into
the formula on the edit bar on the top and hit enter (not changing anything
but I have put the cursor in the edit bar on top) it returns zero, even when
before it had the correct answer and nothing was changed.

The cells D1:D5 are summing up numbers from other sheets.

Please help me because I am going insane!
Thank you SO MUCH!!

MKL