# Chapter 8. Playing with Formulas

In This Chapter

Creating formulas

Using functions

Editing formulas

Manipulating data with goal seeking

Creating multiple scenarios

Auditing formulas

Validating data

Excel can manipulate your data by using formulas. Formulas can be as simple as adding two or more numbers together or as complicated as determining the calculation of a second‐order differential equation.

Formulas use data, stored in other cells, to calculate a new result that appears in another cell. To create even more complicated spreadsheets, you can even make a formula use data from other formulas so that changes in a single cell can ripple throughout an entire spreadsheet.

## Creating a Formula

Formulas consist of three crucial bits of information:

An equal sign (=)

One or more cell references

The type of calculation to do on the data (addition, subtraction, and so on)

A `cell reference`

is simply the unique row and column heading that identifies a single cell, such as A4 or D9. The four common calculations that a formula can use are addition (+), subtraction (–), multiplication (*), and division (/). Table 8-1 lists other mathematical operators you can use in a formula.

A simple formula uses a single mathematical operator and two cell references such as:

=A4+C7

This formula consists of three parts:

**The = sign:**This identifies your formula. If you type just**A4+C7**into a cell, Excel treats it as ordinary text.**Two cell references:**In this example, A4 and C7.**The addition (+) mathematical operator.**

To type ...

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