# Using 'equation split', how can I ensure that only the last equation is numbered?

Consider the following:

$$\begin{split} a & = b + c \\ & = c + d \\ & = d + e \end{split}$$


which outputs

I want to do this so that the equation label (39) is only attached the the final equation, d+e.

How do I go about doing this?

• Should placing the equation number next to the last row be done for all multi-row equations, or should this be done on a case by case basis?
– Mico
May 5 '17 at 22:28
• It should be done for all multi-row equations. It's bad practice to have multiple equations numbered with the same reference, which would technically be the case here.
– ODP
May 6 '17 at 15:41

You seem to be wanting to load amsmath with the tbtags option:

\documentclass[twocolumn]{article}
\usepackage[tbtags]{amsmath}

\begin{document}

$$\begin{split} a & = b + c \\ & = c + d \\ & = d + e \end{split}$$

\end{document}


(Note: twocolumn is just for making a smaller picture.)

The tbtags option for amsmath does just that:

\documentclass{article}
\usepackage[tbtags]{amsmath}
\begin{document}
$$\begin{split} a & = b + c \\ & = c + d \\ & = d + e \end{split}$$
\end{document}


Note that if you'd want to place equation numbers to the left (with option leqno), they'll go to the top of split automatically.

Instead of a {split} environment, use an {aligned}[b] environment; no other changes needed.

\begin{aligned}[b] a & = b + c \\ & = c + d \\ & = d + e \end{aligned}

\begin{align}
a & = b + c \nonumber\\ & = c + d \nonumber\\ & = d + e
\end{align}


Instead split (which has one number vertical centered) you should use align where you allow to number only last line of equation:

\begin{align}
a & = b + c \notag   \\
& = c + d \notag   \\
& = d + e
\end{align}