# Two different numbering styles for equations in the same document

Earlier in the document, there's some equations labeled like this:

(1)  (some space) \frac{1}{/2}=0.5

(2)  (some space) hi


Now, I want to do something like this and switch the equation number and start over:

(a)  (some space) hello


How can I do this?

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Are those really equations? Or is it just an enumeration that just happens to have math in some items? – Manuel Jun 17 '14 at 16:38

Something like this?

\documentclass[leqno,fleqn]{article}
\usepackage{amsmath} %% for \eqref macro
\setlength\textwidth{2in} % just for this example
\begin{document}

$$\frac{1}{2}=0.5 \label{eq:1}$$
$$\mbox{hi}$$

\setcounter{equation}{0}  % reset the equation counter
\renewcommand{\theequation}{\alph{equation}} % change numbering from arabic to alphabetic

Now, I want to do something like this and switch the equation number and start over:
$$\mbox{hello} \label{eq:a}$$

Here are cross-references to equations \eqref{eq:1} and \eqref{eq:a}.
\end{document}

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+1 You might add some labels to show this work correctly too. – Andrew Swann Jun 17 '14 at 19:24
Wouldn't it be better to use two different (custom) environments each with their own counters? equation-arabic, equation-alpha for example? – Thruston Jun 17 '14 at 19:50
@AndrewSwann - Thanks for this suggestion, I'll incorporate in in the answer. – Mico Jun 17 '14 at 20:02
@Thruston - Let's see if the OP weighs in on what he/she is trying to achieve with this change in equation numbering system. – Mico Jun 17 '14 at 20:04
Thanks! It's really interesting though because this only works if I don't include the fleqn. This post is really helpful though. – user54689 Jun 18 '14 at 1:05