During the spring of 2013, WestEd conducted a study of PBS KIDS mathematics transmedia suites in preschool families and communities as part of the Ready To Learn Initiative developed by the Corporation for Public Broadcasting (CPB) and the Public Broadcasting Service (PBS). Transmedia suites are comprised of thematically linked content presented across media platforms. Funded by the U.S. Department of Education, the CPB-PBS Ready To Learn (RTL) Initiative has a goal of promoting early learning and school readiness among young children aged two- through eight-years-old, with a particular interest in reaching children from low-income families. The focus of the current study was to explore the promise of four PBS KIDS transmedia suites (The Cat in the Hat Knows A Lot About That, Curious George, Dinosaur Train, and Sid the Science Kid and their accompanying parent support materials) in increasing preschoolers' mathematics skills and enhancing their parents' ability to support their children's mathematics learning in the home environment. (author abstract)