Some of the smallest problems are sometimes the most annoying. I had a call from a new OpenOffice.org user today who could not find the AutoSum button.
I know how he feels, we sometimes get so used to a certain interfaces that we can struggle with even the smallest change. OpenOffice 3 and its earlier versions have a classic spreadsheet layout and most Excel users (version 2003 and prior) will find the interface instantly recognisable BUT where is, our old favourite, the Autosum button. In Excel this was the Sigma sign normally to be found on the standard toolbar at the top.
With OpenOffice.org Autosum is still the Sigma sign but is on the Formula Bar (when you are clicked in a cell) and of course just with Excel you can type straight into a cell e.g. “=sum(cellref1:cellref2)”
Screenshot below shows the AutoSum button in OpenOffice.org: