Imagine trying to add up dozens, hundreds, or thousands of numbers spread across your spreadsheet. Pointing to each cell individually would become tedious and eventually impossible given enough values (Excel has a limit as to the number of characters in a single cell: 32,767 characters.)
Adding Numbers Using the SUM Function
The SUM function is the single most used function in the entire Excel function library. It has one job: add numbers together to get a total.
If you want to add dozens, hundreds, or thousands of numbers (i.e., cells) together, you don’t have to reference every number (cell), you can just reference the first cell in the series and the last cell in the series.
Assuming your numbers are listed together, your formula would look something like this:
=SUM( C3 : C10 )
The colon character can be thought of like the word “through”.
“What do I get when I sum the contents of cells C3 through C10?”
NOTE: If you only wanted to add the values of two cells that are separated by other cells, you would write the formula as follows.
=SUM( C3, C10 )
The comma character can be thought of like the word “and”.
“What do I get when I sum the contents of cells C3 and C10?”
Because adding values is the MOST performed mathematical operation in Excel, the SUM function gets its own special button called “AutoSum”.
This feature can also be found on the right side of the Home ribbon.
Clicking the AutoSum button will create the formula and even attempt to determine the values needing to be summed.
Other very popular functions can be accessed by clicking the down arrow next to the AutoSum button.