Apply a Sum or Other Function to Every Row in a Data Range in One Step
When you format a data range as a table in Microsoft Office Excel 2007, you can add a calculated column—a column of functions (such as sums or averages)—in just one step. To convert a data range to an Excel 2007 table, click in the range, and then on the Home tab, in the Styles section, click Format as Table, and then click to apply a table style.
When your range is formatted as a table, click in a cell of any empty table column, or a cell in the column directly to the right of the table, on any data row. Then in just that cell, add the function or formula you need. (For example, sum all data on that row of the table.) When you press ENTER to apply your formula in that cell, the entire table column is populated with the same formula, adjusted for each applicable data row. If your insertion point was in the column to the right of the table, Excel formats that column to become part of the table when it generates the calculated column.