As of last night, the current experimental version of the API (which the app uses) returns both
markdown_extensions for sites that require using
\$ to render MathJax (currently only EE and Code Review), so as of the next app update the sites and app will render situations like this the same way.
So I've spent a good chunk of today playing around with this and have reached two conclusions:
The error displayed on the Android app also happens on most MathJax enabled sites, but not on EE.
I can't really come up with a good way of fixing this.
The reasoning for (1) is that EE uses different MathJax settings than most of our other sites, the value we have set up for
inlineMath in the MathJax setup for EE is
[ ["\\$", "\\$"] ], on most sites that have MathJax enabled it is instead
[ ["$", "$"], ["\\\\(","\\\\)"] ].
Since the Android application doesn't have access to the custom settings the sites are using to differentiate their MathJax extensions, we use a combination of all of them. The Android app's value for
[ ["$", "$"], ["\\$", "\\$"], ["\\\\(","\\\\)"] ], a combination of the one that is used just on some sites (EE and a couple others) and the normal one.
This is why the screenshots you posted show it working incorrectly in the Android app, but not on any regular webpage views of the question. The app is incorrectly assuming everything between the dollar sign on the "47" and the dollar sign on the "747" is supposed to be MathJax formatted.
What makes this worse is if you go on one of the sites with the default
inlineMath attribute like math.stackexchange.com, you can recreate this issue. If you post anything that includes two dollar signs all of the text gets parsed by MathJax, so the fact that the answer in question isn't being incorrectly rendered on your other screenshots is actually a weird artifact of EE having different site settings than most of our other sites.
Here's a screenshot from my local development setup, which is currently set to emulate the settings of math.stackexchange.com:
MathJax supports escaping of
inlineMath attributes, by changing the dollar signs in text to
\$ and I've played around with doing different regex search and replaces to do things like "If there is text between two dollar signs and it looks like regular text, not LaTeX, switch the dollar signs to escaped dollar signs" but I've so far been unable to figure out a way to reliably do this that doesn't mess up actual attempts at using MathJax.
Basically, I'm at a loss on what to do here, and you can recreate the bug by visiting a site that uses our normal MathJax settings (math.stackexchange, mathoverflow, CS, stats) and simply putting text between two dollar signs.