In previous lessons, students counted different groups of up to 20 objects and shared with a partner how they counted. In this lesson, students and their partners each count the same collection. This process allows students to compare different ways of organizing and keeping track of objects as they count. It also helps them notice that the total number of objects stays the same regardless of the counting method. As students use and observe a variety of ways to count collections, they begin to understand that the order or arrangement that objects are counted in does not affect the number of objects. Students will further explore the conservation of number when a group of objects is rearranged in a future lesson.

What can the work of the second activity help you learn about your students’ understanding of counting and conservation of number?