I struggle to create a formula that render the cell EMPTY (NOT zero or space).
Here's what I'm trying to do:
A1: 5
A2: IF(A12;BLANK;"NO")
A3: =ISBLANK(A2)

If A1 contains 5 (as above) then the condition in A3 should be TRUE
If A1 contains 1, then the condition should in A3 should be FALSE.

More info: What I'm really trying to do is to automatically insert a default
value in cell A2 if A1 is not empty. This valua can subsequently of course be
overwritten manually. Finally, the sheet should calculate the time-difference
between A1 and A2. Fot this calculation to be correct when NO value is
entered in A1, A2 needs to remain empty in case A1 remains empty because the
simple subtraction of the two cells results in an error if A1 is empty and A2
is not. So I need to find a way to enter a formula in A2 that automatically
places the value that is evaluated as 'EMPTY' or 'BLANK' in A2 without this
same formula screwing up the time-calculation if there is nothing to subtract
in A1 and A2.
Hope this explanation is clear enough....
Thanks very much in advance for your help!
Jop