Project Summary - Leadership There is substantive variation in preschooler’s understanding of the core number concepts (e.g., cardinality) and associated skills (e.g., counting; Geary & VanMarle 2016) that are predictive of later individual differences in readiness to learn formal math at school entry (Geary et al. 2018) and risk of math LD (Chu et al. 2019). Child-centered interventions reduce these gaps (Dumas et al. 2019) but suffer from fade out and thus do not typically confer long-term benefits (Bailey, 2019). Similar fade out is found with individual therapy with young offenders, but sustained gains can be achieved with multisystemic interventions involving the child, home, and school (Henggeler et al. 2009). Future interventions for students who are at risk for math difficulties or math LD will likely need to adopt this multisystemic approach, but most research and training is focused on child-centered factors, such as the development of specific academic competencies or general abilities, such as working memory, that contribute to this development. Although training in these areas is critical, it is relatively narrow and might lead to researchers overlooking contextual factors that could contribute to the development of core early quantitative competencies that support school readiness and risk of math LD. These contextual factors likely include the attitudes and math competencies that parents bring to parent-child conservations about mathematics, the home environment as related academic development generally, and students’ engagement in classroom settings (Gray et al., 2017; Zippert & Rittle-Johnson 2020). To facilitate the next generations’ consideration of the multisystemic factors that influence math learning and risk of math LD, graduate students and a post-doctoral scholar will receive training and experiences in child-centered, parent- and home-centered, and classroom engagement assessments. An early assistant professor (Co-I Rodrigues) who specializes in fractions interventions for students with math LD will serve as a mentee to become familiar with the early mathematics development literature and through this expand her capacity to broadly contribute to future math LD research. She will also work with the team, graduate students, and the post-doctoral scholar on planning a multisystemic intervention for preschoolers who are at risk for long-term difficulties with learning mathematics based on results from a multisystemic (including children, parents, home environment, and classroom experiences) longitudinal study of early mathematics development. The PI and Co-Is have broad expertise in cognitive science, parent-child dynamics, public policy, and intervention research that in turn will provide a unique mentoring experience for graduate students and a post-doctoral fellow that will better prepare them to study and conceptualize the multiple factors that likely contribute to math learning difficulties and math LD.