TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I want my equation's number to be "1'". I have done so through \tag{1'}. But now I don't know how to refer it in my document. Is there a method to call it or numbering equations like 1, 1', 1''?

share|improve this question
I would suggest using \tag{$1^\prime$} rather than \tag{1'} - the \prime is a little cleaner. – Werner Oct 27 '11 at 18:09
@Werner: No, that is still not good. The number 1 should be obtained by a \ref to equation 1. I'll update my answer to show the technic. – Leo Liu Oct 27 '11 at 18:11
@LeoLiu: Oh, so the \prime should be added automatically? – Werner Oct 27 '11 at 18:14
@Werner: I mean the number. There should not be any manual serial numbers in LaTeX. \prime is still typed manaully. – Leo Liu Oct 27 '11 at 18:23
up vote 14 down vote accepted

Use \label and \eqref (or \ref) as usual. I don't think there is any difference.



1+1=2 \tag{A}\label{eq:simple}

Eq.~\eqref{eq:simple} is simple.


(To make this question more useful)

To make a equation as a variant of another one, you can use this:



a+b = b+a \label{eq:comm}

1+2 = 2+1 \tag{\ref{eq:comm}$'$}\label{eq:comm:inst}
              % if hyperref is used, replace \ref with \ref*

Commutative law \eqref{eq:comm} and an instance \eqref{eq:comm:inst}.

share|improve this answer
when i use them, equations are numbered like 1, 2, 3 and so on. What i need is 1, 1', 1'' when i use \tag, i am unable to refer it back. this is the problem – Cagatay Oct 27 '11 at 18:04
Note that you have to use both \tag{<stuff>} and \label{<lab>}, and then you can refer to <lab> with either \eqref{<lab>} or (\ref{<lab>}). Also note the brackets around \ref{<lab>} which is automatically inserted when using \eqref{<lab>}. – Werner Oct 27 '11 at 18:06
Well, then I recover the example I've just deleted. – Leo Liu Oct 27 '11 at 18:07
that has worked, thanks a lot – Cagatay Oct 27 '11 at 18:14
If the "equation variant" version is to be used with hyperref, I wonder whether using \tag{\ref*{eq:comm}$'$} would be better. Otherwise only a portion of the tag will be hyperlinked. It may also be personal preference at this point. – Werner Oct 27 '11 at 18:22

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.