Different states have vastly different curriculums. A third grader from texas moves to california. The math class she's now in may be covering completely differ

Different states have vastly different curriculums. A third grader from texas moves to california. The math class she's now in may be covering completely different material. It might assumes she has mastered skills she hasn't even seen yet. The common core solves that problem by bringing consistency to what subjects are covered when.