If you want to do it through functions so don't have to change your calcs later then you want to use a cell to =SUMPRODUCT(A1:A5,B1:B5) use another cell to =SUM(B1:B5) then in the cell you want to answer to appear you need to divide the SUMPRODUCT cell by the SUM cell.
Last edited by Sandy on Wed Sep 12, 2018 7:14 pm, edited 1 time in total.