Hello I am new here and new to excel so I hope that I am posting this is the right place and explain it correctly.

I need to create the following

a1*d1 however in some of the rows A may be empty and this returns a #value error in the f column which will be summed and prevents a total where rows contained the value error. I do not want the spread sheet user to have to type 0 in the a fields each time. So it is desirable that if A is empty I don't get a value error