# Chapter 4 Introducing Worksheet Functions

**In This Chapter**

- The advantages of using functions in your formulas
- The types of arguments used by functions
- How to enter a function into a formula

A thorough knowledge of Excel’s worksheet functions is essential for anyone who wants to master the art of formulas. This chapter provides an overview of the functions available for use in formulas.

## What Is a Function?

A *worksheet function* is a built-in tool that you use in a formula. Worksheet functions allow you to perform calculations or operations that would otherwise be impossible. A typical function (such as SUM) takes one or more arguments and then returns a result. The SUM function, for example, accepts a range argument and then returns the sum of the values in that range.

You’ll find functions useful because they

- Simplify your formulas
- Permit formulas to perform otherwise impossible calculations
- Speed up some editing tasks
- Allow
*conditional*execution of formulas—giving them rudimentary decision-making capability

The examples in the sections that follow demonstrate each of these points.

### Simplify your formulas

Using a built-in function can simplify a formula significantly. For example, you might need to calculate the average of the values in 10 cells (A1:A10). Without the help of any functions, you would need to construct a formula like this:

=(A1+A2+A3+A4+A5+A6+A7+A8+A9+A10)/10

Not very pretty, is it? Even worse, you would need to edit this formula if you inserted a new row in ...

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