Hi ,
I do not understand your requirement , but try these formulae :
=SUMPRODUCT(($E13:$G13) * A13)
=SUM(($E13:$G13)*TRANSPOSE($A13:$D13)) ; enter this as an array formula , using CTRL SHIFT ENTER.
=SUM(MMULT(TRANSPOSE(OFFSET($E13:$G13,,,5)),OFFSET($A13:$D13,,,5))) ; enter this as an array formula , using CTRL SHIFT ENTER.
Narayan