The AutoSum tool has a variety of uses. Its principal function use it to generate the total or SUM of a series of numbers. To do this, you highlight a row of cells and click once on the AutoSum tool. Excel will then place the total of the highlighted cells in the first available empty cell to the right of the selected range. You can then copy the formula using the Autofill handle. As you drag down, Excel copies the formula making the necessary changes to return the correct total for each row.

The AutoSum tool can also be used to return the total of several columns simultaneously. To do this, just select all the data in each of the columns you wish to total and then click once on the AutoSum tool. Excel generates a formula at the bottom of each column in the first empty cell.

Clicking on the AutoSum tool always creates a formula using the SUM function which returns the total of a given range of cells. However it can also be used with other functions: for example, AVERAGE. To access the other functions, click on the drop-down menu to the right of the AutoSum tool, select the appropriate function and then check to ensure that Excel has correctly guessed the range of cells you want to use as the argument of the function.

If Excel has not guessed the cells you wish to analyse, you can correct it: either by keying in the correct reference or by resizing the range-selection rectangle until it encloses the correct cells. The formula can then be copied using the AutoFill handle.

The AVERAGE function often tends to generated a number containing several decimal places. If you would like a consistent number of decimals, click the Launch button in the Number section of the Home Tab, select "Number" as the category and then enter the number of decimal places you like.

The remaining functions available on the AutoSum tool are COUNT, which tells you the number of cells in the highlighted range containing numbers; MAX, which returns the highest value in the range; and MIN which brings up the lowest value. The final option in the AutoSum tool drop-down menu reads "Other Functions". It gives you full access to Excel's dazzling range of functions.