> I still don't know why long-division works I was taught long division in the 4th grade (age 9) but wasn't taught a proof of why it works until a college alge

> I still don't know why long-division works I was taught long division in the 4th grade (age 9) but wasn't taught a proof of why it works until a college algebra course (age 19). For whatever it's worth a different type of long division is taught now under common core. The common core math stuff that I've seen is impressive - there is more focus on teaching things in a way where comprehension of deeper concepts should be possible. It's a shame there's so much fear of it from parents who are upset kids are learning differently than they did.