If I have a simple formula for cells in a column, e.g. x-y=z, then when I enter the values for x and y I get z; however, if x hasn't been entered I get z=-y. This, of course, happens whatever the formula.
What I would like is for z to remain as a blank cell. This would look better and also I could print out the page for manual use.
I've tried searching - trouble is, I don't know the terms to use and therefore can't ask the question.