I have simple Sum Functions in my Worksheet and they are all correct.

In one of the Cells I only get a minus "-" sign. But the formula in the cell
is correct! =Sum(A1:A12). When I check the formatting under Format Cells I
see that the Format is "Accounting" but even if I change it back to Number or
Custom it doesn't make a change. I can only fix it by copying another Sum
Formula and paste it using Paste Special - Value.

However, this starts to annoy me now. Why is this happening or what am I am
doing wrong that I get those errors in my formulas? Any ideas?

Nicole