# Frequently asked questions - Math

## How do I put a left bracket without including a right one?

The following description applies to both brackets and parentheses.

Math expects that for every opening bracket there will be a closing one. If you forget a bracket, Math places an inverted question mark in place of the missing bracket. The inverted question mark disappears when the opening bracket has a matching closing bracket. This behavior is appropriate the majority of time, when matching brackets make sense mathematically. However, an unpaired bracket is sometimes necessary. In such cases, the solution depends on whether you are using regular non-scalable brackets or scalable brackets.

With non-scalable brackets, use a preceding **\** to indicate that the following character should not be regarded as a bracket but as a literal character. Math will therefore not try to match the corresponding opening or closing bracket.

Display | Math Markup |
---|---|

(-5, 7] | \(-5, 7\] |

[-5, 7) | \[-5, 7\) |

With scalable brackets, use the **left** and **right** Math markup to signal the openings and closings, followed by the symbol to be displayed--choose from **(**, **)**, **[**, **]**, **lbrace**, **rbrace** and **none**.

Display | Math Markup |
---|---|

abs x = left lbrace matrix { -x #, x <0 ## x # , x>= 0 } right none |