Early numeracy skills are vital for kindergarten students because they provide the foundation for acquiring mathematics skills in both kindergarten and subsequent years. Teacher support to intervene on kindergarteners at-risk for poor mathematics learning outcomes is a promising approach to address this achievement gap. The current study replicates previous work on an established early numeracy intervention, ROOTS. In this instance, ROOTS uses remote professional development as a novel format for interventionist training support during the COVID-19 pandemic. Findings indicate that interventionists receiving remote support for implementing ROOTS found training and coaching acceptable and feasible. Remote training and coaching supported strong levels of implementation fidelity. Further, children who received the ROOTS intervention outperformed their control group peers on post-test measures of mathematics achievement within a randomized controlled trial research design. Outcomes and implications for using remote professional development as a format for supporting educators in their use of early numeracy intervention programs are discussed within a pandemic-response context. [This paper will be published in "Prevention Science."]