I implement Google Apps Education Edition in my school.
One of the best things about Google Apps is it gives any student with a gmail account a free spreadsheet. I polled students in math classes and only about 1/3 has spreadsheet software at home. Teachers now can assign math homework that requires the use of a spreadsheet - because now all students will have access to a spreadsheet at home. The spreadsheet also is very good at graphing and is used in both math and geography classes. The Google Apps spreadsheet can both export and import Microsoft Excel files.
Math teachers do not need Google Apps Education Edition to be set up for their students to access Google Docs spreadsheets. Math teachers only have to ask their students to get a free gmail account (they automatically get a free spreadsheet as part of the gmail service).