This paper describes the learning trajectory for Early Equations and Expressions (EELT), one of the 18 learning trajectories presented at www.TurnOnCCMath.net, developed to interpret the Common Core Standards for Mathematics based on research on student learning. The EELT is foundational for introducing concepts of early algebra and setting the foundations for the most advanced mathematical ideas in the later grades of schooling. The theoretical framework and research literature that the unpacking was based on are presented by giving examples from the descriptors of the standards. [Additional support for this research was provided by Qualcomm and the Oak Foundation. For the complete proceedings, see ED584443.]