The SUM function is one of the most common functions to use in spreadsheets. Functions are useful when you want to perform calculations without having to type in the formula (e.g., =(B3+C3+2D3)/4) in the formula bar.

To use the SUM function, you must first select the cell in which the SUM will be stored. Then you can use the AutoSum button on the Standard Toolbar to enter the SUM function.