Spreadsheeting often fits in with the maths department of a school and quite rightly so as it has so many great mathematical niceties. But it is so useful in other subjects and for life skills. Graphing and budgeting (side note graphing is so easily done in other ways) Check out some ideas for getting classes going with spreadsheeting including collaborative spreadsheeting.
Over many years this spreadsheet exercise has grown to be in the state that it is now where it starts from scratch and teaches a whole lot of spreadsheeting fun. From patterns and filling to writing formulas with relative referencing then onto absolute referencing, fixing cells, columns and rows and then into a bit of statistics joy.
It is shared as a Google Sheet for now at bit.ly/spreadsheets101 but will soon be an excel online sheet as well on this page.
While you are waiting! you may like to check out some earlier content written by Rolfe on blogs.newington.nsw.edu.au/ict/google/sheets/