So in which situation do you want the result blank?
I've already given you the formula which will give a blank result if any of
the 3 input cells is blank.
If you want a blank result only if *all 3* input cells are blank, change my
formula from
=IF(COUNT(F7,-D8,E8)=3,SUM(F7,-D8,E8),"") to
=IF(COUNT(F7,-D8,E8)<>0,SUM(F7,-D8,E8),"")

Signature
David Biddulph
> Hi
> Thanks for these, but the main thing I need is to show the cell blank if
[quoted text clipped - 36 lines]
>> >> Thanks
>> >> Mat