SUMPRODUCT is a function that multiplies each cell within range against each other and sums the result together.
This function is often used in conjunction with other functions but it also has utilization as a stand alone function. In the example above, rather than using SUM function in the row 4 and then dragging it for all columns and using SUM function again to add results together; a single SUMPRODUCT function is used. SUMPRODUCT has only one argument:
array1: requires input of cells range that will be multiplied against one another and result added together.