Okay, an Emacs StackExchange person said I'd have to alter the actual
HTML/CSS, that adding #+LaTeX_CLASS_OPTIONS: [oneside,reqno] would not help
the HTML output -- and it doesn't. I did find the HTML section

<script type="text/x-mathjax-config">
    MathJax.Hub.Config({
        displayAlign: "left",
        displayIndent: "5em",

        "HTML-CSS": { scale: 100,
                        linebreaks: { automatic: "false" },
                        webFont: "Neo-Euler"
                       },
        SVG: {scale: 100,
              linebreaks: { automatic: "false" },
              font: "Neo-Euler"},
        NativeMML: {scale: 100},
        TeX: { equationNumbers: {autoNumber: "AMS"},
               MultLineWidth: "85%",
               TagSide: "right",
               TagIndent: ".8em"
             }
});
</script>

where the TagSide "left" can be changed after output by hand to "right",
and that solves the problem. So how would I tell org-mode to make this
change? Is there any control over MathJax from Emacs variables or my
org-mode file?

On Sun, Aug 14, 2016 at 7:25 PM, Lawrence Bottorff <borgauf@gmail.com>
wrote:

> I've got this
>
> \begin{align}
> n &= 0 \\
> n &= m + 1
> \end{align}
>
> in an org-mode buffer. When I produce a Latex output, the numbering n = 0
>     (1) etc. is properly placed on the right. But an HTML output places the
> numbering on the left. What do I need to do to have both HTML and Latex
> output place the equation numbering off to the right? One Latex tip was to
> include \documentclass[12pt,oneside,reqno]{amsart} where t
>