- Introduction
- Understanding Formulas
- Creating a Simple Formula
- Creating a Formula Using Formula AutoComplete
- Editing a Formula
- Understanding Cell Referencing
- Using Absolute Cell References
- Using Mixed Cell References
- Using 3-D Cell References
- Naming Cells and Ranges
- Entering Named Cells and Ranges
- Managing Names
- Simplifying a Formula with Ranges
- Displaying Calculations with the Status Bar
- Calculating Totals with AutoSum
- Calculating Totals with Quick Analysis
- Performing One Time Calculations
- Converting Formulas and Values
- Correcting Calculation Errors
- Correcting Formulas
- Auditing a Worksheet
- Locating Circular References
- Performing Calculations Using Functions
- Creating Functions
- Creating Functions Using the Library
- Calculating Multiple Results
- Using Nested Functions
- Using Constants and Functions in Names

## Creating Functions

**Functions** are predesigned formulas that save you the time and trouble of creating commonly used or complex equations. Trying to write a formula that calculates various pieces of data, such as calculating payments for an investment over a period of time at a certain rate, can be difficult and time-consuming. The **Insert Function** feature simplifies the process by organizing Excel’s built-in formulas, called functions, into categories so they are easy to find and use. A function defines all the necessary components (also called arguments) you need to produce a specific result; all you have to do is supply the values, cell references, and other variables. You can even combine one or more functions.

### Enter a Function Using Insert Function

- Click the cell where you want to enter the function.
- Click the
**Insert Function**button on the Formula bar or click the**Function Wizard**button on the Formulas tab. - Type a brief description that describes what you want to do in the Search for a function box, and then click
**Go**. - If necessary, click a function category you want to use.
- Click the function you want to use.
- Click
**OK**. - Enter the cell addresses in the text boxes. Type them or click the
**Collapse Dialog**button to the right of the text box, select the cell or range using your mouse, and then click the**Expand Dialog**button. - Click
**OK**.