Hello! I don't think you can add a column without doing anything, but you can put a formula that can do a SUM of the whole Column, depending on what kind of SUM you want.

This can be done via the SUM Functions in Excel.

So to simply sum a whole column, you just:

=sum(A:A)

you just put this in a different column to prevent a looping of the formula, which will cause an error. Hope this helps!