Additional completed spreadsheet (with 5 worksheets) based on 'Operation Christmas Tree'. The trees will 'light up' if all answers to the computation problems are correct. The intro worksheet is the same as the one in 'Operation Christmas Tree' and 4 new worksheets have been added (for grades 7 and 8). In addition, there are worksheets that can be printed for students so they can work on the problems before trying to light the trees. Keys are provided as well. NOTE: Excel files updated 12/19/12 to change operator symbols to match worksheets.