In this paper we present the background, aims and methodology of the ScratchMaths (SM) project, which has designed curriculum materials and professional development (PD) to support mathematical learning through programming for pupils aged between 9 and 11 years. The project was framed by the particular context of computing in the English education system alongside the long history of research and development in programming and mathematics. In this paper, we present a Bframework for action^(diSessa and Cobb, Journal of the Learning Sciences, 13, 77-103, 2004) following design research that looked to develop an evidence-based curriculum intervention around carefully chosen mathematical and computational concepts. As a first step in teasing out factors for successful implementation and addressing any gap between our design intentions and teacher delivery, we focus on two key foundational concepts within the SM curriculum: the concept of algorithm and of 360°total turn. We found that our intervention as a whole enabled teachers with different backgrounds and Digit Exp Math Educ (2017) 3:115-138 DOI 10.1007/s40751-017-0028-x The research reported in this paper forms part of a larger project, the ScratchMaths project 2014-17 funded by the Educational Endowment Foundation. The project is being independently evaluated following a randomized control trial model involving over 100 primary schools across England. Department of Informatics Education, Comenius University, Bratislava, Slovakia levels of confidence to tailor the delivery of the SM in ways that can make these challenging concepts more accessible for both themselves and their pupils.