Math on a Merge Field

[Eric]

I am using Word 2007. I am trying to do some simple math on a merge field and
it is turning out to be not so simple. I have a field (tpay) that I need to
take and subtract 15 from. The field returns a numeric value.

If someone could provide me with a way to do this it would be appreciated.

 

[Peter Jamieson]

Try { ={ MERGEFIELD tpay }-15 }

where each pair of the special field braces {} can be entered using ctrl-F9
and everything else is text. Use Alt-F9 to toggle between "field code" view
and "results" view, and select the fields and press F9 to update the result.
Also, look out for a "preview" option.