Edit: it appears that this is not exclusive to ADHD.
Posting this meme stemmed from my own efforts to explain my thought process when doing math and how it is similar to other people with ADHD doing math, while being different from every neurotypical person I'd talked to on the same subject.
While I didn't make the meme itself, instead finding it in my saves and wanting to share, I did accidentally spread misinformation that I had only backed up with personal anecdotal evidence.
I'll leave this up just so people can see the explanation below but this appears to not be ADHD related and just due to different people doing math in their heads differently...
isn't the problem specifically that some people just can't really do intuitive math for small numbers? like all through school everyone else just breezed through memorizing the multiplication tables and i just sat there manually adding numbers together and felt so fucking stupid and worthless in math class
Yeah, everyone pops at their own time. Not everyone gets it quickly.
My daughter is finding this right now; fluency with small numbers isn't coming to her quickly, so we're doing extra review at home to help. Not many parents are equipped to help with number fluency games, though, so it's unfortunately not unusual for many kiddos to hit fractions (or algebra) before they have strong number sense and math hits then like a truck.
If it helps, anyone without significant intellectual delays can learn number sense and work their way back up the math ladder from there. You could go back and work on decomposition of 10, 20, and 100, skip counting forwards and backwards in this progression: 10, 5, 2 (even numbers), 2 (odd numbers). Then for the rest, start with 9, but then from learn from any number: 3/4, 5, 6, 8/9, 7. (You start learning the bigger ones by building off 2s: Skip counting by 3 is 2+1, 4 is 2+2, 8 is 10–2, 9 is 10–1, 7 is hard, but if you have fluency skip counting by 5 from arbitrary numbers, then it's just 5+2.)
I hope that makes sense. A full mental math progression is explained in the Jump Math for Home books at the middle school level.