This article reports on a study of mandatory assessment in mathematics for preschool-class children (aged six) and teachers’ opportunities to advocate Care for the learning of mathematics. Care for learners and Care for mathematics intersected in the teachers’ Grouping of students and their ability to Know the student. These play out as teachers promote availability and justice to students, and as teachers strive to make students’ knowledge visible, promote accuracy and gain legitimacy. It is concluded that teachers’ opportunities to advocate care for the learning of mathematics needs to be present also in the administration of assessment and to be put in the context of the school’s culture and student population, for teachers to be able to promote fair assessment for each student.