I realize this is an old question, but I just found a solution in the Office 365 version of Word, which allows you to reference bookmarks in formulas. I'm not sure of this feature's availability in older versions.
NOTE: This works fine for a small table, or, in my case, to sum just a few select cells in a table. i.e. =SUM(SubTotalA + SubTotalB).
If you have a large table, this would not be very effective, so your options for a large table would be to insert an Excel spreadsheet or write a macro to automate this process.
Steps are as follows:
- Select the first cell you want to reference (make sure you select the whole cell, that seems to matter in my experimenting).
- Go to the INSERT tab on the ribbon, and under the LINKS drop-down select BOOKMARK.
- Add a named bookmark which will point to your cell. i.e. bookmark "A1"
- Repeat for each cell you'd like to create a bookmark for. i.e. bookmark "B1"
- Write your formula and use your bookmark names. i.e. "=PRODUCT(A1,B1)"
- Insert rows/columns and your formula keeps working because the bookmarks seem to maintain the relative reference to the cell.