I tried writing a formula on Why are some equations and formulas written in a way that suggests the smaller number divides the bigger number, instead of the other way around?, but I cannot find the option to show math as when I use shift F10. All I see is a context menu for my web browser. The dollar signs and formula show up as raw text. However, my screen reader can read Math ML and display it in Nemeth code in Braille using MathPlayer by Design Science for those have who converted it.
MathJax provides an accessibility extension that works with a variety of screen readers. For more details concerning MathJax and screen readers, I suggest reading this link on accessibility features in MathJax. Often this is through MathML, as MathJax translates expressions to MathML internally.
I am uncertain how one should use a screen reader to check a MathJax expression while it is being written.
For those who are not sighted, what happens is that there is an input text area, and below that there is a preview area. When a user types a latex expression, it remains plaintext in the input area, but below MathJax renders that text as a math image. This preview area also renders markdown syntax and a few other formatting things specific to StackExchange. I think that this means that in order to use MathJax's MathML when writing a math expression, one would need to navigate to the expression in the preview pane. Unfortunately, I don't know of a good way to do that.