\[
  \frac{a}{b} + \sqrt[3]{x} = \sum_{i=1}^{n} \binom{n}{i} x^i
\]

Delimiters: $\left( \frac{1}{2} \right)$ and $\left[ a, b \right)$.

A small matrix: $\begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}$.
