During Year 3, the Ready To Learn summative evaluation team, comprising researchers from EDC's Center for Children and Technology and SRI International's Center for Technology in Learning, followed up our 2012 Preschool Pilot Study of PBS KIDS Transmedia Math Content by conducting a large-scale, randomized control efficacy study of a PBS Transmedia Math supplement in preschool classrooms. Below is a brief summary of the study and the main findings, as well as our reflections on the themes that emerged from the study. (author abstract)