Code formatting is for code; it is not just a different way to format your text. Don't use it for non-code text. If that means we never use code formatting, so be it. Like all HTML formatting, it actually has a purpose, and using it for non-code text is using it incorrectly.
HTML elements are incredibly meaningful. To you and I, bold text is just thicker, italicised text is just slanted, code text is just a monospace font with a grey background, and they're all just ways of making things look visually distinct. The elements used to produce that formatting, however, mean something different to a visitor's screen reader, a browser trying to handle technical terms or code in special ways, or other machines doing other special things with your HTML markup.
When you appropriate markup for purposes it wasn't intended for, you confuse those machines and give anyone working with them a hard time.
Here's the definition for the element we use for our code formatting (code for inline code, pre for code blocks):
The code element represents a fragment of computer code. This could be an XML element name, a file name, a computer program, or any other string that a computer would recognize.
The pre element represents a block of preformatted text, in which structure is represented by typographic conventions rather than by elements.
Is the text you're supplying either of these? If so, use code markup. If not, don't.
What do we use then?
Italics and bold! Our italic and bold text are represented by the em and strong elements which also have their own definitions:
The em element represents stress emphasis of its contents. (...)
The placement of stress emphasis changes the meaning of the sentence. The element thus forms an integral part of the content. The precise way in which stress is used in this way depends on the language.
The definition of em then goes on to provide examples of how usage of em can and should change the meaning of a sentence. "Cats are cute animals" means something different to "Cats are cute animals": the former is a suitable statement in a discussion about which animals are cute, the latter is a suitable reply to someone who just asserted they are cute vegetables. The two are not interchangeable without you sounding odd.
The strong element represents strong importance for its contents. (...) Changing the importance of a piece of text with the strong element does not change the meaning of the sentence.
Note for those who actually use HTML and may be unaware: b and i are still in use and have their own distinct purposes. They aren't deprecated.
Use MathJax for formulas
Our site nowadays supports MathJax, a derived implementation of \$\LaTeX\$ formulas, which provides us with a means to have well-laid-out equations. You can implement MathJax inline with
\$ ... \$ or in its own line, centered, with
$$ ... $$. It can get a bit complex: see the MathJax basic tutorial and quick reference on Math.SE.
Pick your flavour
So, naturally, these are just two flavours of emphasis. Both will often be read by a screen reader in a different tone of voice to the rest of the text.
Either one works for page numbers; you might prefer italics (YW 212) or just writing your page numbers out with no formatting at all (OW 55); actually using bold may be a bit much visually (YW 209).
You could also use superscriptYW91, since that's a fairly common standard for citations. (In fact, it seems you've used it already!)