Functions are commonly used formulas that are built-in to the spreadsheet program. Functions return values that can be displayed in the worksheet. You must give the function the correct information (called arguments) to make the calculation(s). In Excel, this is not hard, as the program will often suggest the appropriate values.

To view the functions that are built-in to Excel, click on the symbol in the toolbar at the top of the screen. The functions are listed in categories which include financial, date and time, statistical, and so forth. The summation function is so frequently used that it rates it's own button on the tool bar.

The exercise below gives you a chance to to use the summation function:

Exercise: Summing Up the Information in the Worksheet Move your cursor into cell B7 and click on the sum function, found in the toolbar at the top of the screen. Note that cells B3 - B6 are surrounded by a dotted line that seems to move. This shows the cells that will be included in the sum. In cell B7, you see the formula that Excel created for you. It should look something like: =SUM(B3:B6). The colon indicates that the cells are in the same row or column, and all cells in the range will be included in the summation. To tell Excel you want to accept the range of cells to sum as shown, click the checkmark in the function bar or press RETURN. Cell B7 now shows the total (678,200). If you wish to include cells other than those suggested by Excel, you can type the cell addresses directly into the formula. You can also sum non-contiguous cells by holding down the control button, then clicking on the cells to include in the summation. This is the same as typing in a cell address followed by a comma, i.e. =SUM(B3,C7, D13). To sum the total for Expenses, highlight cell B16, and apply the summation function, just as you did for Income in cell B7. The total will be (678,200). For the total to be placed in cell B17, we want to subtract income from expenses. In this particular example, we will have no monies to be returned to the state. We have spent exactly what we are receiving from state revenue resources. Move your cursor into cell B17 and enter the formula =(b7-b16). Since the expenses and income are equal, Excel places a "0" in the cell.