# Math/stackers

< Math

## Overbraces and underbraces

In math mode, you can put a brace over or under an expression this way:

```\startformula
a + \overbrace{b + c} + \underbrace{d + e} + \doublebrace{f + g} + h
\stopformula
```

The same goes for brackets:

```\startformula
a + \overbracket{b + c} + \underbracket{d + e} + \doublebracket{f + g} + h
\stopformula
```

You can adjust where the stackers start and end with the `lt` (left-top), `rt` (right-top), `lb` (left-bottom) and `rb` (right-bottom) parameters. This feature was introduced in beta 2019-10-28.

```\$a + \overbrace  [lt=1em]         {b+c+d} + e\$\blank
\$a + \underbrace [lt=1em]         {b+c+d} + e\$\blank
\$a + \overbrace  [rb=1em]         {b+c+d} + e\$\blank
\$a + \underbrace [rb=1em]         {b+c+d} + e\$\blank
\$a + \overbrace  [lt=1em,rb=1em]  {b+c+d} + e\$\blank
\$a + \underbrace [lt=1em,rb=1em]  {b+c+d} + e\$\blank
```

#### Interleaved braces

Some terms of an expressions can be shared by both braces, tuning the `lt`, `rt`, `lb` and `rb` parameters:

```\$a + \doublebrace[lt=1.4em,rt=-.3em]                   {b+c+d} + e\$\blank
\$a + \doublebrace[rb=1em]                              {b+c+d} + e\$\blank
\$a + \doublebrace[lt=1.4em,rt=-.3em,lb=-.3em,rb=1.5em] {b+c+d} + e\$\blank
\$a + \doublebrace[lt=-1.6em,rb=-1.4em]                 {b+c+d} + e\$\blank
```

• Chapter "1. Math stackers" in the "About" manual.
• Section "1.8 Accents" in the "Still" manual.
• Section "10.6 Fancy fences" in the "Math-mkiv" manual.