This study, part of a narrative classroom inquiry into the teaching and learning of mathematics in a Canadian elementary classroom, emerges from the three years I was a participant-observer in Janine O'Neil's 3rd/4th-grade classroom at Bay Street Community School. Drawing on the curriculum commonplaces of teacher, social milieu, subject matter, and learner, I portray the various viewpoints and interests that shape curriculum of a 3rd/4th-grade lesson. In the process of engaging the various perspectives of the curriculum commonplaces, a challenge to formalistic thinking in and about education develops, which has implications in this time of standardization and central government influences on education. (Contains 1 figure and 1 note.)