The first question was only an attempt to examplify my problem. The long formula in the last question is the exact problem so can I preserve this formula
=(F3*G3)+(I10*J3)+(L3*M3)+(O3*P3)+(R3*S3)+(U3*V3)
and get to threat the last three parenthesises as zero IF one or more of the variables is a blank cell. Following cells could be blank: I3, J3, L3, M3, O3, P3, R3, S3, U3, V3

disregard the first question as it was a faulty attempt to create a fictive example

possible?