The purpose of this activity is for students to compare solid shapes. In making comparisons, students have a reason to use language precisely (MP6). Students choose two solid shapes and describe and record at least one way they are the same and one way they are different. Students may draw pictures or use letters or words to record. Some characteristics students may use to compare the shapes include:

• Size
• Orientation (“the point is facing down”)
• Flat and curved surfaces
• Square, triangular, or circular faces
• Corners
• “Points” (pyramids and cones)

The purpose of the Activity Synthesis is to share the attributes students used to compare shapes. Consider making a list of the different ways that students compared shapes, and remind them of some of these attributes during the next activity. 

• Display a cone and a cube.
• “What is alike, or the same, about these shapes? What is different?” (Both have a flat side. The cube has many points and this shape has only one point.)
• Display 2 different cylinders, one that is thin and tall and one that is wide and short.
• “Describe these shapes to your partner.” (Both have circles on them. Both are solid shapes. One is shorter. One is thinner.)
• “Both shapes are cylinders.”

The purpose of this activity is for students to sort solid shapes in any way that makes sense to them.

Monitor for and select students with the following approaches to share in the Activity Synthesis:

• Shapes that roll and shapes that do not roll
• Shapes with a sharp point and shapes that do not have a sharp point
• Shapes with a circular face and shapes that do not have a circular face
• Shapes with a square face and shapes that do not have a square face

Consider sequencing the student approaches used during the activity from the most to the least common, in order to help students make sense of different ways to compare and describe solid shapes. When inviting students to share, aim to elicit both key mathematical ideas and a variety of student voices, especially from students who haven't shared recently.

If the sorting mat provided in the student book is too small for students to sort the shapes, consider giving students two pieces of construction paper, or ask students to keep the two groups separate in their work area.

• Invite previously selected students to share their approaches in order from the most to the least common. Record or display their work for all to see.
• Connect students’ approaches to the learning goal by asking:
  • “How did _______ sort their shapes?” (Shapes that roll and shapes that don’t roll. Shapes with a point and shapes that don’t have a point. Shapes with a circle and shapes that don’t have a circle. Shapes with a square and shapes that don’t have a square.)
  • “Why did they put this _______ in this group instead of the other group?” (It rolls and the other shapes can’t roll. It isn’t pointy like the other shapes. It has a square on the side and the other shapes don’t have squares. It has a circle on the bottom but the other group has different shapes on the bottom.) 
  Repeat for each students’ work.

The purpose of this activity is for students to learn Stage 4 of the Geoblocks center. Students take turns reaching into a bag and feeling a solid shape without looking. They guess the shape and show it to their partner. Together they check to see if the shape from the bag matches the guess. Students may name the same shape (“It’s a cube.”) or describe an object that looks like the shape. (“This is shaped like a box.”)

After they participate in the center, students choose any previously introduced stage from these centers:

• Counting Collections
• Match Mine
• Shake and Spill

• “Which do you enjoy more: figuring out which shape it is by feeling it or by listening to clues from your partner?”