Thank you so much.
Now, if I enter a number  into the column  which comes out negative, and
then delete it, it has a 0. Clearing the contents of the cell  does not
help. It is not a big issue, but I am wondering if it can be fixed.
If I do not enter anything into the cell, it is clear.
I have the "show zero value" checked, because I need it for other
places, but even if I take it off, the 0 still affects the formula.
That negative  cell is summed with another cell. IF they are both
blank, they have a formula to say "N/A". However if enter something
into the negative cell and then need to delete it, the result is not
N/A because it still has a 0.

I hope that is somewhat clear!
Again, if it is complicated to fix, the roll  book will still be fine.
Once again I thank you for making my preparations for school easier!