In LaTeX, you will always use curly brackets. But, you cannot use direct like other brackets while using in document.

```
\documentclass{article}
\begin{document}
\[ {a_1,a_2, \cdots, a_n} \]
\[ (b_1,b_2, \cdots, b_n) \]
\[ [c_1,c_2, \cdots, c_n] \]
\[ |d_1,d_2, \cdots, d_n| \]
\end{document}
```

**Output :**

Solution to this problem is to use a backslash before both curly brackets. Let’s see if it is executed or not!

```
\documentclass{article}
\usepackage{amssymb}
\begin{document}
\[ {a_1}, \{a_2\}, {a_3}, \{a_4\} \]
\[ S_n = \{1,2,3,\cdots, n\} \]
\[ S_n = \{a_1,a_2,a_3,\cdots, a_n\} \]
% Don't used adjustable curly bracket
\[ \mathbb{Q} = \{ \frac{p}{q} | a,b \in \mathbb{Z}, b\neq 0 \} \]
\[ \{\frac{a_1}{n}\} , \{\frac{b_1}{m}\} , \{\frac{c_1}{k}\}\]
\end{document}
```

**Output :**

## Adjustable size of curly bracket

In the code above, a mathematical expression was given to you to understand, where size of mathematical equation was larger than curly brackets.

It seems like a big problem to you but its solution is very simple. For this, LaTeX has a built-in command that adjusts size of bracket according to size of expression.

```
\documentclass{article}
\begin{document}
\[ \{a_1\}, \left\{\frac{a_2}{k}\right\}, \{a_3\}, \left\{\frac{a_4}{k}\right\} \]
\[ S_n = \left\{\frac{n(n+1)}{2}\right\} \]
\[ S_n =\left\{\cfrac{\sum\limits_{i=1}^{n} {s_i}}{n}\right\} \]
\[ \mathbb{Q} = \left\{ \frac{p}{q} | a,b \in \mathbb{Z}, b\neq 0 \right\} \]
\[ \left\{\frac{a_1}{n_1}\right\} , \left\{\frac{b_1}{m_1}\right\} , \left\{\frac{c_1}{k_1}\right\} \]
\end{document}
```

**Output :**

Second, you can manually increase size of bracket, but there are limitations in this case.

```
\documentclass{article}
\begin{document}
\[ \big\{\sigma\big\} \; \Big\{\sigma_{ij}\Big\} \; \bigg\{\frac{\sigma}{n}\bigg\} \Bigg\{\frac{\sigma_{ij}}{n_k}\Bigg\} \]
\[ \big\{ \Big\{ \bigg\{ \Bigg\{ x \Bigg\} \bigg\} \Big\} \big\} \]
\[ \big\{ r \big\} \Big\{ e \Big\} \bigg\{ a \bigg\} \Bigg\{ d\Bigg\} \]
\end{document}
```

**Output :**

## Use newcommand

If you frequently use a specific size of curly bracket in your documents, you can define a new command using the “\newcommand” command. This allows you to define a custom command that can be easily reused throughout your document.

```
\documentclass{article}
\newcommand{\curly}[1]{\left\{ #1 \right\}}
\newcommand{\curlb}[2]{#1\{ #2 #1\}}
\begin{document}
\[ \curly{x} \curly{\frac{x}{y}} \]
\[ \curly{\frac{n(n+1)}{n}} \curly{\frac{a}{b}} \]
\[ \curlb{\big}{a} \curlb{\Big}{b} \curlb{\bigg}{c} \curlb{\Bigg}{d} \]
\end{document}
```

**Output :**

## Use physics package

Many of you may be familiar with the physics package. But, did you know that this package has an in-built command for curly brackets! Let’s see its use

```
\documentclass{article}
\usepackage{physics}
\begin{document}
\[ \qty{x} \; \qty{\frac{x}{y}} \]
\[ \qty{\frac{n^2 + 1}{n}} \]
\[ \qty\big{m} \qty\Big{a} \qty\bigg{t} \qty\Bigg{h} \]
\[\Bqty{\frac{n^2 + 2n + 1}{n}} \]
\end{document}
```

**Output :**

For `\qty`

command, curly brackets will be automatically adjustable with expressions.

Along with `\qty`

command, you can use the big command. But, in this case the process of using big command is completely different.

## Use curly bracket in Matrix

You’ll notice that matrices are bounded by curly brackets. You don’t need to use separate brackets for this. Just pass `Bmatrix`

argument to matrix environment.

```
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[ \begin{Bmatrix}
a_{11} & a_{12} & \cdots & a_{1n}\\
a_{21} & a_{22} & \cdots & a_{2n}\\
\vdots & \vdots & \ddots & \vdots\\
a_{m1} & a_{m2} & \cdots & a_{mn}
\end{Bmatrix}
\times
\begin{Bmatrix}
b_{11} & b_{12} & \cdots & b_{1p}\\
b_{21} & b_{22} & \cdots & b_{2p}\\
\vdots & \vdots & \ddots & \vdots\\
b_{n1} & b_{n2} & \cdots & b_{np}
\end{Bmatrix}
=
\begin{Bmatrix}
c_{11} & c_{12} & \cdots & c_{1p}\\
c_{21} & c_{22} & \cdots & c_{2p}\\
\vdots & \vdots & \ddots & \vdots\\
c_{m1} & c_{m2} & \cdots & c_{mp}
\end{Bmatrix} \]
\end{document}
```

**Output :**