# Write, insert, or change an equation

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Microsoft Office Word 2007 includes built-in support for writing and editing equations. Previous versions used the Microsoft Equation 3.0 add-in or the Math Type add-in. Equation 3.0 was included in previous versions of Word and is available in Office Word 2007. Math Type was not included in previous versions of Word but was available for purchase.

** Note ** The Equation command is unavailable in Compatibility Mode. To turn off Compatibility Mode, convert the document to the Word 2007 file format. For more information, see the section Convert your document to Office Word 2007.

If an equation was written in a previous version of Word and you want to edit the equation by using Office Word 2007, you need to use the add-in that was used to write the equation. If you purchased Math Type, you need to have Math Type installed.

- Write an equation
- Insert a frequently used or preformatted equation
- Insert a commonly used math structure
- Change an equation that was written in Office Word 2007
- Change an equation that was written in a previous version
- Convert your document to Office Word 2007

## Write an equation

To write an equation, you can use Unicode character codes and Math AutoCorrect entries to replace text with symbols. For more information, see Insert a symbol or special character.

When you type an equation, Word automatically converts the equation into a professionally formatted equation.

- On the
**Insert**tab, in the**Symbols**group, click the arrow under**Equation**, and then click**Insert New Equation**.

- Type an equation.

## Insert a frequently used or preformatted equation

- On the
**Insert**tab, in the**Symbols**group, click the arrow next to**Equations**, and then click the equation that you want.

### Add an equation to the list of frequently used equations

- Select the equation that you want to add.
- Under
**Equation Tools**, on the**Design**tab, in the**Tools**group, click**Equation**, and then click**Save Selection to Equation Gallery**. - In the
**Create New Building Block**dialog box, type a name for the equation. - In the
**Gallery**list, click**Equations**. - Select any other options that you want.

## Insert a commonly used math structure

- On the
**Insert**tab, in the**Symbols**group, click the arrow under**Equation**, and then click**Insert New Equation**.

- Under
**Equation Tools**, on the**Design**tab, in the**Structures**group, click the structure type that you want, such as a fraction or a radical, and then click the structure that you want. - If the structure contains placeholders, click in the placeholders and type the numbers or symbols that you want. Equation placeholders are small, dotted boxes in an equation .

## Change an equation that was written in Office Word 2007

- Click the equation that you want to edit.
- Make the changes that you want.

## Change an equation that was written in a previous version

To change an equation that was written in a previous version by using the Equation 3.0 add-in or the Math Type add-in, you need to use the add-in that was used to write the equation.

When you open a document that contains an equation that was written in a previous version of Word, you cannot use the built-in support for writing and changing equations unless you convert your document to Office Word 2007.

### Change an equation that was written by using Equation 3.0

- Double-click the equation that you want to edit.
- Make the changes that you want.

To get help in Equation Editor, click **Equation Editor Help Topics** on the **Help** menu.

### Change an equation that was written by using Math Type

To change an equation written with Math Type, you need to have Math Type installed.

- Double-click the equation that you want to edit.
- In Math Type, edit the equation.
- On the
**File**menu, click**Close and Return to**.*name of the document that contains the equation*

To get help in Math Type, click **Contents and Index** on the **Help** menu.

## Convert your document to Office Word 2007

If you convert your document and save it as an Office Word 2007 file, you will not be able to use previous versions of Word to change any equations in the document.

Click the **Microsoft Office Button** , and then click **Convert**.

- Click the
**Microsoft Office Button**, and then click**Save**.

** Note ** After you convert your document, you need to save the document as an Office Word 2007 document, or the document will revert to the previous version.