Sometimes it's easier to copy formulas than to create new ones. In this example, you'll see how to copy the formula you used to get the January total and use it to add up the February expenses.
First you select cell B7, which contains the January formula. Then, position the mouse pointer over the lower-right corner of the cell until the black cross (+) appears. Next, drag the fill handle over cell C7. When the fill handle is released, the February total 126.93 appears in cell C7. The formula =SUM(C3:C6) is visible in the formula bar near the top of the worksheet whenever you click in cell C7.
After the formula is copied, the Auto Fill Options button appears to give you some formatting options. In this case you wouldn't need to do anything with the button options. The button disappears when you next make an entry in any cell.
Note You can drag the fill handle to copy formulas only into cells that are next to each other, either horizontally or vertically.