I am using align*, but I still need an equation number. I know one solution is to use align and add \nonumber to all lines but the last. Is there a 'lazy' way to do it?

I searched a little and found similar ones suggesting use split: Show equation number only once in align environment

Unfortunately, due to the page break issue I have, I need to use align, because split won't auto page break, as described in Long equation does not page break.


Use \tag:

a &=b \\
  &=c \numberthis \label{eqn}
Equation \eqref{eqn} shows that $a=c$.
d = e

See page 3 of the amsmath package documentation for details.

  • Why didn't you use \stepcounter or \refstepcounter instead of \addtocounter? – kiss my armpit Aug 31 '13 at 6:14
  • @PSTikZ --- \refstepcounter isn't needed, as the \ref value is set correctly already. \stepcounter is probably the best choice, to take care of subsidiary counters. I don't think I gave much thought to this when I composed the answer. – Ian Thompson Sep 2 '13 at 8:25
  • Your example works perfectly for me, thank you. I have a followup question though. How can I make the number on the same line than the last line of the euqation provided that the last line is longer normal align would allow (it does fit in align* though) – magu_ Mar 24 '14 at 9:56
  • 1
    @magu_ Please post a new question with an example showing exactly what you want. I think I understand your question, but I'm not 100% sure. Also, other users (who may have better solutions than me) will see the new question, whereas they are unlikely to see new comments here. – Ian Thompson Mar 24 '14 at 12:04
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    This solution has a problem when combined with the cleveref package: The sorting of \numberthis-references does not work properly. See this question for further detail. If anyone knows a solution fixing this problem, please let me know. – Lukas Sep 30 '16 at 15:32

Another option is to use align, and then use \nonumber, as mentioned in http://mirrors.dotsrc.org/ctan/info/math/voss/mathmode/Mathmode.pdf.


a &=b \nonumber \\
b &=c
Equation \eqref{eq:test} shows that $a=c$.
  • 5
    The user seems to want to use an align* environment, though. Your approach would involve a lot of \nonumber, if the align contains a lot of lines. – jub0bs Feb 26 '14 at 9:50
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    Welcome to TeX.SX! This answer, while technically correct, is already mentioned in the second sentence of the question; the asker is looking for a different solution. – ChrisS Feb 26 '14 at 9:51
  • I must have misread the question. I did not see that. Sorry. – martinweiss Feb 27 '14 at 13:03

Here are minimal working examples that I use. This is what I have as a header


Two equations each with separate equation numbers and separate reference labels

        \dot{a} &  =2\alpha(t)\eta\label{classicalmotion1}\\
        \dot{\eta} &  =-2\gamma(t)a\label{classicalmotion2}%

Two equations with a single equation number and a single reference label

        \dot{A} &  =2i\alpha(t)B\\
        \dot{B} &  =2i\gamma(t)A

I am guessing you know how to do the one without equation numbers.

  • thanks! somewhat surprisingly putting the \label(eqn2.qo} before \begin{aligned} changed the position of the eqn number in my case... – Xi'an Oct 26 '14 at 16:38
  • @Xi'an -- putting the \label before the align might change the position of the equation number, but it will also give an incorrect value with \eqref. – barbara beeton Jul 13 '17 at 1:50

Another solution.

a &=b \\
  &=c \tag{\ref{eqn}} 
  • Try having two equations like that, you will see that this code doesn't work. – user156344 Apr 5 at 13:44
  • @user156344: tried and it works as well (of course your need to change the equation labels). – user2477759 Sep 10 at 13:58

protected by jub0bs Feb 26 '14 at 9:51

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