Auto Calc on all sheets on active cells

Is there a way (with or without macros) that can add up all the cells in all work sheets and enter them on a workssheet that will house the results.

For example;

Sheet1 Cells: A1= 10 B1 = 20 C2= 5
Sheet2 Cells: A1= 20 B1 = 20 C2= 10
Sheet3 Cells: A1= 15 B1 = 10 C2= 10

Results sheet Cells:A1= 45 B1 = 50 C2= 25

Any help...Much appreciated.

BOB