I'd like to be able to sum into a blank cell a series of non-consecutive
cells by clicking on them, i.e. by clicking in an empty cell and then hitting
= to start a formula and then clicking the cells I want to add one by one.
Excel 2002's default is to REPLACE the last cell clicked on when you click
after cells one after the other, I want them to add together. Some versions
of Excel (eg. Office 98 and X for Mac) do this by default. Can this be set
up in Office 2002 also?

Thanks in advance.