When using Excel XP functions play an important role in finding values for a range of cells. Learn all about using functions in Excel XP.

A **function** is a **predefined formula** that helps perform common mathematical functions. Functions save you the time of writing lengthy formulas. You could use an Excel function called **Average**, for example, to quickly find the average of range of numbers. Or you could use the **Sum** function to find the sum of a cell range. Excel XP contains many different functions.

Each function has a specific order, called **syntax**, which must be strictly followed for the function to work correctly.

Here is the syntax order:

- All functions begin with the equals (=) sign.
- After the equals sign, define the
**function name**(e.g., Sum). - Add one or more
**arguments**—numbers, text, or cell references—enclosed by parentheses. If there is more than one argument, separate each by a comma.

Here's an example of a function with one argument that adds a range of cells (B3 through B10):

Here's an example of a function with **more than one argument** that calculates the average of numbers in a range of cells (B3 through B10 and C3 through C10):

Excel has hundreds of **functions** to help with your calculations. Building formulas can be difficult and time consuming. Excel's functions can save you a lot of time and headaches.