I use the Trachtenberg speed system of mathematics to do mental math. I can reliably do any 2 digit by 2 digit number and most of the time do 3 by 3 digit numbers. Does anyone know if it’s possible for an adult (I’m 26) to do better with soroban training? The book I had as a kid (translated from japanese) said I would never get good at it after the age of 12.. but that sounds kind of defeatist to me.