The Math for Young Children Project was designed using the Japanese lesson study framework. Each teacher team (consisting generally of 5 to 7 individuals) works closely with the mathematics education research team led by Dr. Cathy Bruce and Dr. Joan Moss across a series of sessions (ranging between 5 to 7 sessions). Each teacher-researcher team begins with deciding on a topic of study (e.g., spatial reasoning in the early years). They then design one-on-one interview activities. Teachers then choose six students from each of their classrooms to administer these activities with. After this initial assessment stage, the teacher-researcher team discuss what they have found and use this knowledge as foundation on which to design further exploratory activities to try out in their classrooms. As exploration deepens with time, the teachers and researchers design a research lesson that is refined and then publicly taught on Public Lesson Day. After the public lesson day, the teacher-researcher team gather again with a rich array of artifacts that are compiled and refined into a complete resource package.