This article reports on an ethnographic study of a 10-year-old's pursuit of school-based mathematics across school and home to suggest that participating in school-based mathematics is a cross-setting phenomenon in at least 2 ways. First, I illustrate how accomplishing school-based mathematics literally extends into the home and how individuals recruit resources from their histories of participation in alternative settings to accomplish the work of school-based mathematics. Second, I show how a youth's social identification in the classroom is shaped by his teacher's partial accounts of how learning is arranged for in the home. Approaching participation in school-based mathematics as a cross-setting phenomenon illustrates the complexity inherent in participating in schooling and raises questions about how to coordinate schooling across school and home settings. (Contains 5 footnotes and 4 figures.)