Our gifted program (with admission heavily weighted towards verbal skills, leaving aside many bored & talented math students) compacts 4-6 grade EM into grades 4-5. The gifted teacher said it was really easy to do by removing the repetition. I actually wonder if that will be harder or easier to do in Common Core.
The program starts much too late, and is much too inflexible as to who can participate, IMO.
FWIW, my reading of the CC standards looks really, really slow. I foresee more boredom, not less, for those kids quick to catch onto new concepts.
