Common Core is a standerd proposed by the U.S. Gov't to set teaching in a certain way. It doesn't make teaching 100% the same, but it is also proposed so that the states have education a little more common to each other. IDK too much about it. I heard a little about it from my AP govt teacher in high school of my senior year (last year) I know Texas, my state, flat out REJECTED IT, and of course nobody in my class was too suprised.