If you've studied the Common Core State Standards for Mathematics' CONTENT STANDARDS, you've realized that transitioning to the CCSS-M will take more careful planning than simply 'flipping the switch' from the GLCE to the CCSS-M.
The Michigan Department of Education has released grade-level documents that identify grade-level gaps in switching from the GLCE to the CCSS-M. These documents clarify the extra content that each grade-level should teach to ensure all students are gap-free in their learning. Teachers only need to teach the extra content until students have come up through the grades under the CCSS-M.
In each document, each grade level has the CCSS organized by critical area, and with content shifts identified that need to be considered in the first year of full implementation of the CCSS.