There are two main ways to add multiple cells with SUM in Excel:

1. Using the SUM function:

This is the most common and flexible way to add multiple cells. Here's how to do it:

* Click on the cell where you want the sum to appear.
* Type the equal sign (=) to initiate a formula.
* Type SUM(, then within the parentheses, specify the range of cells you want to add. You can do this by:
* Clicking and dragging your mouse to select the cells you want to add.
* Manually typing the cell references separated by commas (e.g., A1:A10, B2, C5).
* Close the parentheses.
* Press Enter.

Excel will automatically calculate the sum of the specified cells and display the result in the chosen cell.

2. Using AutoSum:

This is a quicker option for adding a simple range of cells. Here's how:

* Click on the cell where you want the sum to appear.
* Go to the "Home" tab on the Excel ribbon.
* In the "Editing" group, click the "AutoSum" button (Σ).
* Excel will attempt to guess the range of cells you want to add based on the surrounding data.
* If the selection is correct, press Enter to confirm.
* If the selection is incorrect, adjust the range using your mouse or keyboard and then press Enter.

AutoSum is a convenient option for adding adjacent cells, but it can be less flexible for non-contiguous ranges or specific cell selections.

Examples:

* To add cells A1 to A10, you can use the formula `=SUM(A1:A10)`.
* To add cells B2, C3, and D5, you can use the formula `=SUM(B2,C3,D5)`.

By using either the SUM function or AutoSum, you can efficiently add multiple cells in your Excel spreadsheets.