Using AutoSum for Quick Calculations in Excel 2010
You can use the AutoSum button in Excel 2010 to quickly sum a row or a column of values in an Excel worksheet. The AutoSum button is located in the Editing group of the Home tab. When you click this button, Excel inserts the built-in SUM function into the active cell and simultaneously selects what the program thinks is the most likely range of numbers that you want added together.
Click a cell below (or to the right of) the values you want to sum.
This tells Excel which values you want to sum.
Click the AutoSum button in the Editing group on the Home tab.
Excel inserts an equal sign followed by the SUM function and a suggested range of values to sum, displayed in a marquee.
The marquee adjusts to surround the range of cells you select.
Excel enters the SUM formula in the cell.
Although the AutoSum button's primary function is to build formulas with the SUM function that totals ranges of numbers, that's not its only purpose. You can have the AutoSum feature build formulas that compute the average value, count the number of values, or return the highest or lowest value in a range — all you have to do is click the drop-down button that's attached to the AutoSum command button on the Home tab and then click Average, Count Numbers, Max, or Min on its drop-down menu.