There are two main ways to sum a column or row in Excel:

1. Using AutoSum:

This is the quickest and easiest method for most users.

* Click on the empty cell below the column or to the right of the row you want to sum. This is where the sum will be displayed.
* Go to the "Home" tab on the Excel ribbon.
* In the "Editing" group, locate the "AutoSum" button (Σ).
* Clicking this button will automatically:
* Insert the formula `=SUM( )` into the selected cell.
* Excel will intelligently highlight the range of cells it assumes you want to sum (the column or row above/to the left of the selected cell).
* Press Enter to confirm and calculate the sum.

2. Using the SUM function manually:

* Click on the empty cell where you want the sum to be displayed.
* Type the following formula: `=SUM(range)`. Replace "range" with the actual cell range you want to sum.
* For a column: specify the entire column, for example, `=SUM(A1:A10)` would sum cells A1 to A10.
* For a row: specify the entire row, for example, `=SUM(B2:G2)` would sum cells B2 to G2.
* Press Enter to confirm and calculate the sum.

Tips:

* You can also select the cell range you want to sum and then type the formula `=SUM( )` directly into the formula bar (located above the worksheet).
* AutoSum is a great time saver, but the manual method gives you more flexibility to define the specific range you want to sum.
* Remember, Excel cells can contain text or errors (#VALUE, #NA) - these will be included in the sum unless you use specific functions to handle them differently.