# Frequently asked questions - Math

From The Document Foundation Wiki

## When I enter one of the symbols **#**, **&** , **|**, **^** or **_** I get an error message or an undesired result. How can I use these symbols?

These symbols have special meanings in Math:

- The
**#**symbol is used with**stack**and**matrix**. - The symbols
**|**and**&**are used to indicate logical or and logical and, respectively. - The symbols
**^**and**_**are used to indicate superscripts and subscripts, respectively.

To use one of these symbols in a formula, put it in quotation marks. For example: **"#"**.

There are two uses of the **|** symbol for which Math has specific markup:

**a divides b**will display a | b**abs a**will display |a|