# Lesson 5

## Warm-up: Number Talk: Divide by 7 (10 minutes)

### Narrative

This Number Talk prompts students to rely on properties of operations and the relationship between multiplication and division to divide within 100. The reasoning here helps students develop fluency in division.

### Launch

• Display one expression.
• “Give me a signal when you have an answer and can explain how you got it.”
• 1 minute: quiet think time

### Activity

• Keep expressions and work displayed.
• Repeat with each expression.

### Student Facing

Find the value of each expression mentally.

• $$70\div7$$
• $$77\div7$$
• $$63\div7$$
• $$56\div7$$

### Activity Synthesis

• “How did you use facts you know to find facts you didn’t know?” (I used $$70\div7$$ and thought about one more group to find $$77\div7$$. I used $$70\div7$$ and one less group to find $$63\div7$$.)

## Activity 1: All the Ways (20 minutes)

### Narrative

The purpose of this activity is to deepen students’ understanding that a shape can belong to multiple categories because of its attributes. Students analyze shapes and determine all the ways that each one could be named. The names may refer to a broad category such as triangle or quadrilateral, or a narrower subcategory such as rhombus or rectangle. As they name the different categories students need to be precise both about the meaning of the categories and verifying the properties of the different shapes (MP6).

MLR8 Discussion Supports. Synthesis: For each observation that is shared, invite students to turn to a partner and restate what they heard using precise mathematical language.
Engagement: Provide Access by Recruiting Interest. Leverage choice around perceived challenge. Invite students to select at least 4 of the 6 problems.
Supports accessibility for: Organization, Attention, Social-Emotional Skills

### Launch

• Groups of 2
• “Look at the quadrilateral in the first problem. Work independently to circle all the names that you could use to describe the quadrilateral. Be prepared to share your reasoning.”
• 1 minute: independent work time
• 2 minutes: partner discussion
• Share responses.

### Activity

• “Complete the rest of the problems independently. Be prepared to explain your reasoning.”
• 3–5 minutes: independent work time
• 5–7 minutes: partner discussion
• Monitor for students who notice that some shapes can be described using multiple terms.

### Student Facing

Select all the ways you could describe each shape. Be prepared to explain your reasoning.

1. triangle
3. square
4. rhombus
5. rectangle

1. triangle
3. hexagon
4. rhombus
5. rectangle
6. square
1. triangle
3. pentagon
4. rhombus
5. rectangle
6. square

1. triangle
3. hexagon
4. rhombus
5. rectangle
6. square
1. hexagon
3. triangle
4. square
5. rectangle
6. rhombus

1. hexagon
3. triangle
4. rhombus
5. rectangle
6. square

### Student Response

If students use only one name for a shape that can be named in multiple ways, consider asking:

• “How did you describe the shape?”
• “Are there any other names that could be used to describe the shape?”

### Activity Synthesis

• Select 1–2 students to share the terms they selected for each of the last four quadrilaterals and their reasoning.
• “Who can restate _____’s reasoning in a different way?”
• “Does anyone want to add on to _____’s reasoning?”
• “Do you agree or disagree? Why?”
• “The last shape can be described with 4 of the choices. How is it possible that it can be described in so many ways?” (It is a quadrilateral because it has 4 sides. It is a rhombus because it’s a quadrilateral with 4 sides that are the same length. It is a rectangle because it has 4 right angles and 2 pairs of sides that are the same length. It is a square because it has 4 sides that are the same length and 4 right angles. The last three are more specific descriptions of a quadrilateral.)

## Activity 2: Draw One That’s Not . . . (15 minutes)

### Narrative

The purpose of this activity is for students to apply what they know about the defining attributes of rectangles, rhombuses, and squares to draw shapes that are not those quadrilaterals. They use geometric attributes to explain why their drawings meet the criteria.

### Launch

• Groups of 2
• “Take a minute and think about how you could draw a shape for each one of these descriptions.”
• 1 minute: quiet think time

### Activity

• “Now, work with your partner to draw a shape for each statement. Be ready to explain how you know each shape matches the description given.”
• 7–10 minutes: partner work time

### Student Facing

1. Draw a quadrilateral that isn’t a square.

2. Draw a quadrilateral that isn’t a rhombus.

3. Draw a quadrilateral that isn’t a rectangle.

4. Draw as many quadrilaterals as you can that aren’t rhombuses, rectangles, or squares.

### Activity Synthesis

• Select students to share their drawings and explanations for the first three problems.
• Highlight explanations that include the defining attributes of squares, rectangles, and rhombuses.
• Invite students to share as many different quadrilaterals as they can think of for the last problem. Display as many as possible.

## Lesson Synthesis

### Lesson Synthesis

“How has your thinking changed over the last few lessons about what a quadrilateral can look like?” (Before, when I thought of quadrilaterals, I thought of rectangles and squares, but now I know they can look so different. Some have right angles and some don’t. Some have sides with equal length and some don’t. They all look really different even though they have some things in common.)

## Student Section Summary

### Student Facing

In this section, we learned to sort shapes based on attributes such the number of sides, side lengths, and whether angles were right angles. We also sorted quadrilaterals and triangles into more specific groups.

We learned that a shape can be named based on its attributes. For example:

• If a triangle has a right angle, then it is a right triangle.

• If a quadrilateral has 2 pairs of sides that are the same length and 4 right angles, then it is a rectangle.

• If a quadrilateral has sides that are all the same length, then it is a rhombus.

• If a quadrilateral has sides that are all the same length and 4 right angles, then it is a square.