The importance and complexity of young children’s mathematical thinking and learning warrants high-quality, research-based resources that help teachers and caregivers understand and support children’s development from birth through the primary grades. The authors discuss young children’s potential to think mathematically, the criticality of early math, and the need for a learning trajectories approach to early math. Describing existing risks to young children’s experience of high-quality math, the chapter offers solutions to these risks in systematic research and development of technology-based resources for early math using learning and teaching with learning trajectories ([LT]2, at LearningTrajectories.org) as an example. Further, the authors advocate for a lens of equity, inclusion, and accessibility in the development of these technologies. Finally, a vision is described for increasing access to high-quality math through adaptive technologies that use the learning trajectories of early math for in-person and online activities.