Start with a blank worksheet and duplicate the worksheet by typing the information in the corresponding worksheet cells.

Select the cell where the result of the addition is going to be displayed and type the "=" equals sign. Now, click on the Worksheet Menu button and select Paste Function. From the Select Function dialog box, select the SUM function. Now, select the cells range and click on the green check mark. You can specify the range of the cells by clicking on a cell and then dragging the mouse. You can also specify the range of the cells by typing the range (Example: B2..B5). The double periods designate the range of the cells.