# Choose which rows in multi-line equation to assign numbers to [duplicate]

If i do:

\begin{align}
a = b \\
b = c \\
c = d \\
\end{align}


The output will be like:

(1)        a = b
(2)        b = c
(3)        c = d


If I use algin* instead. No row will be enumerated.

Is there a way to get the following output?

           a = b
b = c
(1)        c = d

-
See for example tex.stackexchange.com/questions/65207/… and the linked questions. –  Torbjørn T. Apr 15 '13 at 9:36

## marked as duplicate by Mico, mafp, Charles Stewart, Claudio Fiandrino, KurtApr 15 '13 at 11:01

Rather than choosing which rows to enumerate you could let mathtools enumerate only the equations you reference.

\documentclass{article}

\usepackage{mathtools}

\mathtoolsset{showonlyrefs}

\begin{document}

\begin{align}
a = b \\
b = c \label{eq:unused} \\
c = d \label{eq:used} % Only this row will be enumerated as it's the
% only row that is referenced to.
\end{align}
\eqref{eq:used}

\end{document}

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That's exactly what I was looking for! Than you very much. –  htellez Apr 15 '13 at 11:43
It didn't work as well as I expected. All my \refs point to the first \subsubsection above them and no equation is being enumerated. –  htellez Apr 15 '13 at 11:48
@htellez Did you try eqref rather than ref? –  N.N. Apr 15 '13 at 13:00
That was exactly the problem. Thank you so much. –  htellez Apr 15 '13 at 19:15