\begin{equation} ... \end{equation}. Finding modern resources to learn LaTeX (and indeed TeX for macros etc) has been a perennial difficulty for me!

Or \[ ... \] for unnumbered equations.

I would use

  \begin{equation*}
    ...
  \end{equation*}

for consistency and ease of switching between numbered and unnumbered.

It's true, finding modern LaTeX tutorials is even harder that modern c++. It shares many of the same problems.

We put together a LaTeX course (in german) for physics student every year and keep it up to date with best practices as much as possible: http://toolbox.pep-dortmund.org/files/archive/latest/latex.p...