Equation

Tier

rich

Surfaces

page

Fallback

readable

State

settled

Display maths, in the $$ spelling GitHub and Obsidian already render.

$$
\int_0^1 x^2 \,dx
$$

A paragraph whose whole content is one piece of inline maths is an equation block, so a one-line $$E = mc^2$$ is the canonical form for maths with no line break in it, and the fenced form above carries maths that has one.

Single-$ maths is not recognised, in either direction. Reading it would turn $5 and $9 in a sentence into an equation, which is a false positive nobody can spell their way out of.

Nothing is computed: the TeX is the author's, kept byte for byte, and the product only draws it.

Fallback: renderers with maths draw it; the rest show the TeX as text — the words are all still there.