alt Hacker NewsI watched the video. I think I've been wanting something like this recently but there's not really a name for this sort of thing that I know of.
Relatedly, I've been working on a step-by-step solver/calculator but I just use sympy (via pyodide) + mathlive. But I'm starting to see the limitations of running Python in the browser and am starting to look at js libraries now.
The underlying math engine is written in typescript and is open source:
https://github.com/dicroce/wyrm_math
Probably it's most important feature for applications like this is that the id's of elements in the equations are stable (meaning, if an X has an id of 123 and a transformation moves it to the other side of the equals sign, it still has id 123... this allows you animate between states if you wish).