shortcuts
Pressing alt-= will also invoke AutoSum
Click AutoSum a second time instead of enter to accept the default range
The down arrow on the right of the AutoSum button accesses different commonly-used functions (btw, the AutoSum button looks like a captial greek sigma)
Select a range terminated by a blank cell, click AutoSum and Excel will sum the range into the blank cell; select a range without a blank cell and the results are not always predictable (in my experience, it offers a =SUM() in the first cell to overwrite your entry)
Select all your data bounded bottom and right by blanks and Excel will sum rows, columns and give a grand total at the bottom right (usually by summing the column totals - always an impressive time-saver!)
