What is there to practice with latex? You either get it right or you make child support payments for the next 18 years.
I've expended several hours trying to understand what happens with the LaTex version at this site, PLUS my own Firefox navigator.
As far as I understand. any browser has embedded several script versions to decode LaTex commands.
The failure resides on HOW your HTML5 code at your browser decodes LaTex commands, because HTML5 add an important amount of
HTML5 formatting commands between the [math] and [\math]. And THIS aditional HTML5 commands make the LaTex parser to crash!
The huge problem is that it's invisible to your eyes, and the only way to SEE THEM is to analyze the page in HTML5 source code mode.
That's how I detected the problem: the intrusive HTML5 formatting commands are INVISIBLE to your eyes, and you observe nothing in your
browser. But, if you select Tools --> Web Developer --> Page Source, the differences will appear.
This problem can make you mad easily, as you can't observe what is doing HTML5 in the background of your page. It's almost random.
If you copy and paste a LaTex formula, MAYBE it's copied literally. Even if you are copying a functional LaTex formula one paragraph below
the one that works.
The best solution (for me), is to make a fresh start with a new page. If you are working with text and later use LaTex and it doesn't work, better
to copy the text in a notepad, restart the page where you were writing and write (by hand) the LaTex code first.
Then, after this, you copy back your text that saved at the notepad.
Try observing my post here in HTML5 mode, and find the equations that work and that don't. You'll understand what I'm trying to explain.
How to solve this crazy problem? I don't know. The server of this forum has a LaTex script parser and renderer embedded, while in other
forums the server that compute LaTex is from a third party, so formulae are processed outside the forum and imported as GIF automatically.
I can't tell you more than this. It can make you to lose your temper due to the frustration.