Grade 3 LearnZillion Math consists of 15 units and a total of 155 lessons. Each lesson is designed to be completed in one 45-55 minute class period. Each unit includes a summative Unit Assessment designed to be completed in one class period, this assessment day is not included in the number of days allotted to lessons. The organization of the units, and lessons within each unit, creates a coherent sequence based on the progressions of the standards. As shown in the figure below, the majority of lessons are focused on the major work of Grade 3. The remaining lessons focus on supporting or additional clusters, often in the service of the major work. In third grade, 72% of lessons (112 lessons) are devoted to the major work of the grade. Many lessons dedicated to major work standards are enhanced and deepened by simultaneously engaging students in standards from supporting or additional clusters. In some instances when appropriate, students work only with supporting or additional work clusters.