\documentclass{article}
\usepackage{latexml}
\begin{document}
\lxDeclare[role=ID]{$a$}%
\lxDeclare[role=ID]{$b$}%
\lxDeclare[role=ID]{$c$}%
\lxDeclare[role=ID]{$d$}%
\lxDeclare[role=ID]{$e$}%

\section{Basic math}
\[ ((a + b) - c) \]
\[ (a + (b - c)) \]

\section{Intervals}
\[ (a,b) \]
\[ [a,b) \]
\[ (a,b] \]
\[ [a,b] \]

\section{Cases}

\[ \left.\begin{array}{l} a \\ b \end{array}\right\}
  = \left\{\begin{array}{l} c\\ d\end{array}\right. \]

\[ \left(\begin{array}{l} c\\ d\end{array}\right) \]
\[ (a + \left(\begin{array}{l} c\\ d\end{array}\right) + b) \]

\section{Atop}
\[ a + { b \atop c } + d \]
\[ a + \left[ b \atop c \right] + d \]


\section{Delimiters}
\[ \left( {a \over b} \right) \]
\[ \left[ {a \over b} \right] \]
\[ \left\lbrack {a \over b} \right\rbrack \]
\[ \left\{ {a \over b} \right\} \]
\[ \left\lbrace {a \over b} \right\rbrace \]
\[ \left\lfloor {a \over b} \right\rfloor \]
\[ \left\lceil {a \over b} \right\rceil \]
\[ \left< {a \over b} \right> \]
\[ \left\langle {a \over b} \right\rangle \]
\[ \left| {a \over b} \right| \]
\[ \left\vert {a \over b} \right\vert \]
\[ \left\| {a \over b} \right\| \]
\[ \left\Vert {a \over b} \right\Vert \]
\[ \left\uparrow {a \over b} \right\downarrow \]
\[ \left\Uparrow {a \over b} \right\Downarrow \]
\[ \left\updownarrow {a \over b} \right\Updownarrow \]

\def\foo{\langle}
\def\bar{\rangle}
\[ a + \left\foo {b \over c} \right\bar + d \]

\[ {a \over b} \left/ {c \over d} \right. \]

\end{document}
