The purpose of this activity is for students to begin to distinguish rectangles from other shapes. This sorting task gives students opportunities to analyze shapes closely and make connections (MP7). By working with variants and nonexamples of rectangles, students begin to develop their understanding of what makes a shape a rectangle. When they discuss which group a shape should be placed in, students informally describe the attributes of the shape.

• “How did you choose which group to put this shape in?” 
• “What is alike or the same, about all shapes in this group?” 

• Invite students to share their sort.
• Draw or display a square:

  

• “Into which group did you put this shape?” (We put it with the rectangles because it has 4 sides. We didn’t put it with the rectangles because it is a square.)
• “This shape is a square, which is a special rectangle because all 4 sides are the same length.”

• Display the last problem.
• “Use ‘longer than’ to describe these rectangles.”
• “Use ‘shorter than’ to describe these rectangles.”
• Invite students to chorally repeat these words or phrases in unison 1–2 times:
  • “The yellow rectangle is longer than the red rectangle.”
  • “The red rectangle is shorter than the yellow rectangle.”
• Rotate the book so that the yellow rectangle is on top:

  

• “Which rectangle is longer?”
• “The yellow rectangle is longer than the red rectangle.”

The purpose of this activity is for students to choose from activities that offer practice with number and shape concepts.

Students choose from any stage of previously introduced centers:

• Counting Collections
• Which One?
• Picture Books
• Bingo
• Shake and Spill

• “What was something that felt challenging during centers today? Why did it feel challenging?”