I will be putting dates into cells in column A and B. I will use Row1 as
the reference for my question.
If I have dates in A1 and B1 I need to calculate the number of intervening
months - I used =Datedif(a1,b1,"m"). If both cells are empty, I the number
zero is returned. If one cell is empty, I get #Num. If both are populated,
I get the correct answer.
I want to supress both the 0 and the #num. I tried
=if(iserror(and(isblank(a1),isblank(b1)),"",datedi f((a1,b1,m)),"",if(and(isblank(a1),isblank(b1)),"" ,datedif((a1,b1,m)))

It doesnt work, and I can not figure out what is wrong.

Please help.