Hi Kizatie, welcome to the forum.
SUMPRODUCT should work for you in this case. See the attached workbook for an example, and let us know if you need additional assistance figuring out the formula(s) needed. If you look in the formulas on the Summary tab in row 2, the only thing that changes is the last column reference.
$C$2:$F$8, $C$2:$N$8, $C$2:$AB$8 (I made up that last one since you didn't have weekly data out to column AB.)
Hope that helps!
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