Previous versions of Access enabled you to add summary calculations to your reports, but if you viewed your data as a datasheet, the datasheet itself didn’t contain the summary. That meant you either had to create a report that contained a summary calculation at the end, build a query that totaled the values in one or more fields, or do some quick mental arithmetic. In Access 2007, you can add a Totals row to a datasheet, bypassing the need to create a specific report or query to calculate the total.
Display a form in Datasheet view.
Click the Home tab.
In the Records group, click Totals.