Social justice might be considered too complex a topic to address with 6- and 7-year-olds, particularly through mathematics. How would first-graders understand social justice? The author believes that by focusing on inequality in relation to power and access to resources, freedom, and diversity, children could understand social justice issues. The author stresses that two ways children can deepen their understanding are through experience and literature. Engaging children in a mathematics project around issues of social justice could provide experience and also allow the author to understand the children as mathematicians. This article presents the author's mathematics project that provides opportunities for the children to demonstrate the various levels and the breadth of their mathematics knowledge.