Lesson 1 introduces students to multiplication starting with the concept of repeated addition. They learn to recognize each circled group as a unit, this will help them to understand the vocabulary of groups and unit form. Lesson 2 then allows students to relate equal groups of objects in a scattered arrangement and transition into an array model. They then begin to understand that each row of the array is a group (review of Lesson 1). Lastly, Lesson 3 solidifies students' ability to differentiate the meaning of factors by the number of equal groups multiplied by the size of the group.