In this article, South Africa provides an "outlier" case study that illuminates the tensions that exist between locally responsive mathematics education interventions, aimed at tailoring initiatives to the vastly unequal contexts of schooling, and the systemic "one size fits all" interventions of the state. I draw on the experiences of two teachers involved in an in-service teacher intervention project, to argue that our current curriculum and systemic "support" fail to accommodate the extreme backlogs in learner knowledge.