# Lesson 6

Rectangles and Squares

## Warm-up: What Do You Know About Triangles? (10 minutes)

### Narrative

The purpose of this warm-up is to introduce students to a new routine called What Do You Know About _____? In this routine, students share what they know about triangles. Students may share examples of objects in the world that look like triangles or may describe attributes of triangles.

### Launch

• Groups of 2
• “What do you know about triangles?”
• 30 seconds: quiet think time
• 1 minute: partner discussion

### Activity

• Record responses.

### Student Facing

What do you know about triangles?

### Activity Synthesis

• “Where do you see triangles in your community?”
• Draw or display a triangle and a rectangle:
• “How are these shapes different?”

## Activity 1: Sort Rectangles (10 minutes)

### Narrative

The purpose of this activity is for students to begin to distinguish rectangles from other shapes. By working with variants and non-examples 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.
MLR8 Discussion Supports. Students should take turns finding a match and explaining their reasoning to their partner. Display the following sentence frames for all to see: “I noticed _____, so I matched . . . .” Encourage students to challenge each other when they disagree.

### Required Materials

Materials to Copy

• Rectangle Sort Cards

### Required Preparation

• Cut out rectangle cards from the blackline master. Each group of 4 needs 1 set of cards.

### Launch

• Groups of 4
• Give each group a set of cards.
• Draw or display a rectangle:
• “Tell your partner two things you know about this shape.” (There are 4 sides. It looks like a door. It is a rectangle. It is long and flat.)
• 30 seconds: quiet think time
• 30 seconds: partner discussion
• Share and record responses.
• If needed, ask “What is the name of this shape?”
• 30 seconds: quiet think time
• “This shape is a rectangle.”

### Activity

• “Work with your group to sort the shapes into two groups. Put the shapes that are rectangles on the left side of your page. Put the shapes that are not rectangles on the right side of your page. When you place a shape, tell your group why you think the shape belongs in that group.”
• 4 minutes: small-group work time
• “Write a number to show how many shapes are in each group.”
• 1 minute: independent work time
• “Which group has fewer shapes? How do you know?”
• 30 seconds: quiet think time
• 30 seconds: partner discussion

### Student Facing

Let’s put the shapes into 2 groups.

Rectangle

Not a Rectangle

### Student Response

If students put shapes other than rectangles into the group of rectangles, consider asking:

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

### Activity Synthesis

• Invite 1–2 groups to share how they sorted the shapes.
• Draw or display a square:
• “Which group did you put this shape in?” (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 four sides are the same length.”

## Activity 2: Compare Length of Rectangles (10 minutes)

### Narrative

The purpose of this activity is for students to use longer and shorter to compare the length of rectangles. Because the endpoints are lined up, students should be able to visually see which rectangle is longer, which allows them to practice using language as they develop their understanding of length (MP6).
Representation: Access for Perception. To support access for students with color blindness, use verbal emphasis, gestures, and labeled displays to differentiate between colors and objects.
Supports accessibility for: Visual-Spatial Processing, Conceptual Processing

### Launch

• Display the image or draw the shapes:
• “What is the same about these shapes? What is different about them?” (They are both rectangles. The red rectangle is taller, or longer, than the blue rectangle.)
• “Which rectangle is shorter?” (The blue rectangle is shorter than the red rectangle.)

### Activity

• “Circle the rectangle that is longer. Tell your partner how you know which rectangle is longer.”
• 1 minute: partner work time
• Repeat the steps with the second problem.
• “Circle the rectangle that is shorter. Tell your partner how you know which rectangle is shorter.”
• 1 minute: partner work time
• Repeat the steps with the last two problems, first with longer and then with shorter.

1.

2.
3.
4.

### Activity Synthesis

• 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?”
• “Even though we turned them, the yellow rectangle is longer than the red rectangle.”

## Activity 3: Centers: Choice Time (25 minutes)

### Narrative

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

### Required Materials

Materials to Gather

### Required Preparation

• Gather materials from:
• Counting Collections, Stage 1
• Which One, Stage 1
• Picture Books, Stages 1–3
• Bingo, Stages 1 and 2
• Shake and Spill, Stages 1 and 2

### Launch

• “Today we are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Think about what you would like to do first.”
• 30 seconds: quiet think time

### Activity

• Invite students to work at the center of their choice.
• 10 minutes: center work time
• “Choose what you would like to do next.”
• 10 minutes: center work time

### Student Facing

Choose a center.

Counting Collections

Which One

Picture Books

Bingo

Shake and Spill

### Activity Synthesis

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

## Lesson Synthesis

### Lesson Synthesis

Draw the shapes: “Today we worked with rectangles and squares. What is the same and what is different about these shapes?” (Both of these shapes are rectangles. The red shape is a special kind of rectangle that has sides that are all the same length. The blue rectangle has 2 longer sides and 2 shorter sides.)

If needed, ask “Which rectangle is longer?” (The blue rectangle is longer than the red rectangle.)