Dear Max

Thanks again for your valuable informatin like as always. It worked
very well.
However although I am familiar with sumproduct and ISNUMBER command
but couldnt understand how the combination works out.
As a second question, after conducting filter, only for printing
purpose, I want to add a sequential number column to my list however
it doesnt work. Is there any solution for adding a sequential row
number to a filtered list?

Thanks in advance
Rasoul Khoshravan