I am having trouble figuring out the spreadsheet bundle.  Suppose I have the following table:

|name |foo |bar |total |
|mike  | 1  |  2  |       |

How do I calculate the total?
From the screencasts, I think I should have this line:

% A3 := SUM(A1:A2)

Then what do I need to do to get the cell to display the value? 

Mike