You didn't read the whole reply, did you? Yes, the AutoSum button will do
this. My point was that the Formula dialog doesn't: it doesn't replicate the
behavior of the AutoSum button and consequently is a very inefficient
substitute.
My reply explained how to insert a Sum(Above) or Sum(Left) field in Word
2007 (where the AutoSum button is not, by default, available); it then
explained how to add the AutoSum button to the QAT.
For the benefit of others who may be coming in late, here's the whole
message:
"After you have created a table, you will have two contextual table tabs:
Design and Layout. On the Layout tab, in the Data group, there is a Formula
button that opens the Formula dialog, where you can select the Sum function.
If you want it to be Sum(Above) or Sum(Left), as created by the AutoSum
button, you'll have to type this in yourself.
"Not quite the answer you wanted, is it? So click on the arrow at the end of
the QAT, choose More Commands..., select Commands Not in the Ribbon, scroll
down to Sum, and click Add >>."
I should probably have preface this by saying: "Word 2007 doesn't have an
AutoSum button by default; the procedure that replaces it is quite tedious."