Latex numbering equations. We’ll see how to number the Latex equations using the leqno and fleqn header functions.

Number the equations on the right: fleqn

To number the equations on the right, we use the argument fleqn in the class of the document: \documentclass. For example, in the case of an article in A4 format of size 10 points:

\documentclass[a4paper,10pt,fleqn]{article}
\begin{document}
   \begin{eqnarray}
   7x + 4y & =  & 0 \\
   2x - 5y & =  & 0
    \end{eqnarray}
\end{document}

Which gives:

Number the equations on the left: leqno

To number the equations on the left, we use the argument leqno dans la classe du document: \documentclass. For example, in the case of an article in A4 format of size 10 points:

\documentclass[a4paper,10pt,leqno]{article}
\begin{document}
   \begin{eqnarray}
   7x + 4y & =  & 0 \\
   2x - 5y & =  & 0
    \end{eqnarray}
\end{document}

Which gives:

Delete the numbering of a line: \ noumber

To delete the number of a line we use the command \nonumber. This command must be placed at the end of the line whose number is to be deleted just before the line-break symbol (\) if it exists obviously!

\begin{eqnarray}
  -\Delta  u & =  & f \\
  u & =  & 0 \nonumber 
\end{eqnarray}