Adoption of the Common Core State Standards present challenges to school districts, school administrators, and teachers. To assist in this endeavor, we present our work on unpacking the CCSS-M for the length, area, and volume Learning Trajectory (LT). The overarching theme of "genetic epistemology" and a five-characteristic framework guided our work of unpacking the Standards. As a result, we added "Bridging Standards" to mediate students' progression through the length, area, and volume LT to provide a coherent structure through this trajectory. The implications of our work were discussed. [Additional support for this work was provided by the Oak Foundation. For the complete proceedings, see ED584829.]