I need to find a way of solving the following in Excel. I think it is a called a matrix, but I do not know the type.

.................G1 ....... G2............. G3........

.................X1........ X2 ..............X3......

................X1G1 .....X1G2..... .....X1G3

.............................X2G1 ...... ...X2G2 ......X2G3

...............................................X3G 1 ......X3G2....... X3G3

SUM= ....... Y1..........Y2 ...............Y3................................. .......

I want to get the values of the series of sums (Y values) I have up to 15 values for X1 and G2 so I need to have a automated approach in Excel for solving 15 value for the sums of the Y values in the vertical columns. Can this be done in Excel? It is very labor intensive and error prone to do it manually in Excel.

Angus