The SUM function in excel adds the numerical values in a range of cells. Being categorized under the Math and Trigonometry function, it is entered by typing “=SUM” followed by the values to be summed. The values supplied to the function can be numbers, cell references or ranges.

- Return value : The sum of values supplied.

Syntax

`=SUM (number1, [number2], [number3], ...)`

- Arguments

*number1* - The first value to sum.

*number2* - [optional] The second value to sum.

*number3* - [optional] The third value to sum.

Example:

Typically, the SUM function is used with ranges. For example:

```
=SUM(A1:A9) // sum 9 cells in A1:A9
=SUM(A1:F1) // sum 6 cells in A1:F1
=SUM(A1:A100) // sum 100 cells in A1:A100
```

Values in all arguments are summed together, so the following formulas are equivalent:

```
=SUM(A1:A5)
=SUM(A1,A2,A3,A4,A5)
=SUM(A1:A3,A4:A5)
```