On the Weighted Average sheet in cell F6 create a weighted average formula: Assignment 1 score divided by the Out of score times the Weight, plus Assignment 2 score... then fill down to F. In M6 create a simple formula to multiply quantity times cost, and fill it down to M9. The SUM function is already built into M10. In M12 use SUMPRODUCT to multiply all the quantities and costs and sum them up (a much simpler way to get the same result). Select cells A13 through E14 and name the cell ranges. Use the Formulas | Create from Selection technique. In F16 use SUMPRODUCT to create the weighted average. Fill down to F19. Move on to the next sheet