Despite this being the disfavored explanation, it’s probably mostly genetic combined with congenital non-genetic brain differences.
I’m extremely good at anything verbal or language-based. And I can study 100x or even 1000x as long anything involving math and never achieve really anything. Yes, even if I understand the concept or practicum at the time perfectly, can do all the practice problems and apply it. As soon as I move on from that, it’s gone like smoke in the wind. It’s like I never learned it.
Whereas if I only glance for something for a second or two in the language realm, I’ll remember it forever.
It obviously is just built in and people hate that idea. Nevertheless, it’s true.
I do wonder, though, if some of my math incapacity comes from actual brain damage. I’m pretty sure I used to be a good deal better at math before I got hit in the head a lot as a kid and young teenager.
But what happened happened; can’t change it now.