> Also the way i learned to divide in my head is completely backwards and, though it works for me, when i tried to explain it to my wife i realized how complete

> Also the way i learned to divide in my head is completely backwards and, though it works for me, when i tried to explain it to my wife i realized how completely backwards and inefficient it is, so maybe common core helps with these and other hard-to-internalize concepts? What way? The classic way to learn is to be proficient at multiplication up to 10x10 and then solve for the reverse.