As increasing numbers of Black immigrant students attend schools in Chile, we examine classroom practices to consider the limits of the mathematics education equity promise for this student population. We focus on the practices of a third-grade teacher who participated in professional development for enhancing reform-based mathematics teaching in a racially diverse classroom. Drawing on Stuart Hall's approach to race, our analysis shows how two technologies of race-power fabricate the Black immigrant child as an uneducable and impossible mathematics learner. We contend that rather than enhancing the inclusion of Black immigrant students, reform-based mathematics teaching might maintain and reinforce racial hierarchies of mathematics ability.