Nice and quick. It works on multiple columns; select all the cells in a row below a range of numbers, hit Alt+=, and all the columns get added up. Select cells to the right and all the rows get added.

Editor's note: This is the second in a two-part series about the colorful "Colonel" William C. Greene, who is credited with developing mines in Cananea, Sonora. The years 1899 through 1906 were ...