This Problem Set is a part of the Lesson 1, Unit 1, Grade 3. In this lesson, students begin understanding multiplication as the total number of objects in a number of equal-sized groups. They do a group counting activity and then work with counters to see the relationship between repeated addition, writing groups in unit form, and multiplication sentences. For example, they express 12 as 2 + 2 + 2 + 2 + 2 + 2, "6 twos," and 6 × 2.