Realgorithm

Remember when your teacher taught you to write the equal signs in a single vertical straight line? Reason? They look neat of course!

If you just keep on using \[ ... \] over and over again, LaTeX will only aligned it centre, so unless your equations are of the exact same length the equal signs will not form a single vertical line. Using \begin{subequations} … \end{subequations} will not do. LaTeX will still centralise the equations. So?

\begin{eqnarray*}
10+9-4+8   & = & 19-4+8 \\
& = & 15+8 \\
& = & 23 \\
& \leq & 24
\end{eqnarray*}

anything put between the &…& will be aligned vertically straight.