As promised, here is the first of a week's worth of addins/powertoys for OneNote 2007. This addin will sum the columns of a table for you and add the new row to the bottom. It ignores non-numeric values in the column. It's only requirement is that you need to click in a table to select it before hitting the Sum button (although it will prompt you for clicking the table if you need to).
It does have some limitations. Inking (writing numbers in tables w/o converting them to text) is not supported, and tables within tables will cause problems.
(Updated 3/11/09 to remove dead links and put images back).
Here's the link for the setup file: http://johnguin.members.winisp.net/Shared%20Documents/table_sums.zip
Alternate location: http://elhombre.members.winisp.net/api/table_sums.zip
And the source code: http://johnguin.members.winisp.net/Shared%20Documents/table_sums_Source.zip
Alternate location: http://elhombre.members.winisp.net/api/table_sums_Source.zip
Standard setup directions apply: ensure OneNote has exited, run setup.exe (as an admin on Vista) and install for all users.
Here it is in action. Before adding the columns:
There is a lot to do with this from here. Adding support to sum rows (relatively easy, but requires some new UI), performing other simple math routines, completely ignoring columns which have no numbers at all, perhaps applying boldface to the answers and similar tasks would all be appreciated. Moving this code over to the Object Model at www.codeplex.com/onom and extending it there is also a task on my radar.
As always, let me know what you think.
Questions, comments, concerns and criticisms always welcome,