i'm 30 years old and can't properly multiply or divide on paper. i just, didn't understand why the process worked the way i did for addition or subtraction, and as a result i never ever remembered it

for math tests where i'd have to divide before "no calculators allowed" stopped being the point, i'd quickly memorize the process five minutes before the test and that would get me through it, but i'd forget by the end of the school day

and i was never able to do multiplication, where you multiplied each digit by all the digits in the others in the other number, i think? and wrote down the answers below the problem but shifted some of them left by some number of places, then added them together. don't get it. what i do get is the properties of repeated addition in particular, so my math tests often had margins with columns of numbers doubling over and over until i got close, then some adding up of that number with previous numbers in the column. generalizing the ability to multiply by 2, i guess