# 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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