The purpose of this activity is for students to organize shape cards into three categories and name the categories. Students describe how they sorted and how many shapes are in each category. This sorting task gives students opportunities to analyze shapes closely and make connections (MP7). Students create a representation of how they sorted in the next activity.

Monitor for different ways groups choose to categorize the shape cards, but especially for categories that distinguish between pattern, number of sides or number of corners.

As students work, encourage them to refine their descriptions of the shapes on the cards using more precise language and mathematical terms (MP6).

• Invite previously identified groups to share.
• “How did this group sort their shapes? How many shapes are in each category?” (They sorted by pattern. There are 6 solid shapes, 3 lined shapes, and 3 dotted shapes.)

The purpose of this activity is for students to represent how they sorted their shapes in the previous activity. Then they use their representations to tell how many shapes in each category and how many in all. At the end of the activity, display each representation on tables or walls, to use during the Gallery Walk in the next activity.

• “You created representations to show how you sorted shapes into 3 categories.”
• “In the next activity, we will have a chance to look at and interpret each other’s representations.”

The purpose of this activity is for students to interpret different representations of how shapes were sorted into three categories. Students use the different representations to determine how many shapes are in each category. During the Activity Synthesis, students discuss aspects of representations that make them easier to interpret.

• Display previously identified representations. 
• “How did this group sort their shapes? How many are in each category? How do you know?”
• Repeat with different student work as time allows. 
• “What about this representation helps you understand how this group sorted their shapes? Why does it help?” (The numbers tell me how many shapes without having to count. The labels tell me what the groups were.)