How can I assign an equation number to this matrix equation?

Question

I want to assign an equation number to the following matrix equation; I want a number in brackets on the right side, after the equation.

\[
  \begin{bmatrix}
    1 \\
    2 \\
    3 \\
  \end{bmatrix}
\]

But adding \begin{equation} \end{equation} around this throws an error at \[. How can I number this matrix equation properly?

Answer 1

Replace \[ with \begin{equation} and \] with \end{equation}.

A complete MWE:

\documentclass{article}
\usepackage{amsmath} % for 'bmatrix' environment
\begin{document}
\begin{equation}
  \begin{bmatrix} 1 \\ 2 \\ 3 \end{bmatrix}
\end{equation}
\end{document}

For more on \[... \], the equation environment, and still other methods for creating displaystyle equations, see What are the differences between $$, \[, align, equation and displaymath?