“When I was a kid I figured out my own way to do something like that, but much easier. In that example, I would subtract 300 from 568 to 268, then add back 7 and get 275. Worked well for simple math, but since I didn’t learn the right way I had problems with higher math. Never did get algebra.”
Indeed, your way shows you’re already a couple of quantum levels beyond the Common Core trolls.
As for algebra, we could get you up to speed in no time. (I would even try with the Obamadork, there’s no hope there for anything advanced.)
I even tried again as an adult, but got completely lost when it got to sines. Fortunately 99% of people never actually need to know algebra in their adult lives.