Steps to Delete a Column:

1. Highlight Cells in the columns you want to remove:
   

   

2. Click Edit, Delete Column on the menu:
   
3. You will be prompted for confirmation, click Yes.
   
   
4. Columns are removed:
   

NOTES:

Formulas will be updated accordingly.  For example, formulas that refered to D before we deleted columns B and C will now refer to B.