# Lesson 3

Attributes that Define Shapes

## Warm-up: Number Talk: Multiply Multiples of Ten (10 minutes)

### Narrative

This Number Talk prompts students to use place value and properties of operations to multiply single-digit numbers by multiples of ten. The strategies elicited here help students develop fluency.

### 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.

• $$4\times40$$
• $$8\times40$$
• $$7\times40$$
• $$9\times40$$

### Activity Synthesis

• “How were you able to use $$4\times40$$ to find the other products.” (I doubled $$4\times40$$ to find $$8\times40$$. Once I knew $$4\times 40$$, I could count up or down by 40 to get the other products.)
• Consider asking: “Why might it be helpful to first think of each expressions as multiplying a number and 4 instead of 40?” (We know many multiplication facts for 4, and that 40 is 4 tens. We can think of each problem as groups of 4 tens instead of groups of 40.)

## Activity 1: Learn How to Play Mystery Quadrilateral (10 minutes)

### Narrative

The purpose of this activity is to introduce the game Mystery Quadrilateral and strategically consider the questions that could be asked next to determine a mystery quadrilateral. Students play a round of this game against the teacher. In the next activity, students will play this game in groups of 2.

### Required Materials

Materials to Gather

### Required Preparation

• Gather a set of quadrilateral cards from the previous lesson.

### Launch

• “We are going to play a game called Mystery Quadrilateral. Read the directions independently."
• 1 minute: quiet think time

### Activity

• “Now let’s play a round together. I’ll be Partner A and the class will be Partner B.”
• Play a round of the game.

### Student Facing

1. Partner A: Choose a shape from the group of quadrilaterals. Place it in the mystery quadrilateral folder without your partner seeing it.
2. Partner B: Ask up to 5 “yes” or “no” questions to identify the quadrilateral. Then guess which quadrilateral is the mystery quadrilateral.
4. Switch roles and play again.

### Activity Synthesis

• “What kinds of questions might help you figure out the mystery quadrilateral?” (Questions about something we didn’t already know about the shape. General questions to narrow down the type of quadrilateral, then more-specific questions to figure out which one.)

## Activity 2: Play Mystery Quadrilateral (25 minutes)

### Narrative

The purpose of this activity is for students to practice describing geometric attributes of a quadrilateral with increasing precision by playing a game. Students should be encouraged to ask questions like, “Are all the sides the same length?” rather than, “Is it a square?” to keep the focus on attributes of the quadrilateral rather than the name. As students decide which questions to ask they think about important attributes such as side lengths and angles and have an opportunity to use language precisely (MP6, MP7).

Students will use the quadrilaterals from the previous lesson to hide in the “mystery quadrilateral” folder, but will have a copy of all the shapes in their workbook to support them in asking questions to narrow down the shape. Students can also cover shapes in their workbook with counters as they rule out shapes.

MLR8 Discussion Supports. Synthesis: Think aloud and use gestures to emphasize the attributes that students use to describe the shapes. For example, trace your finger along the angles and sides of the shape as students describe them.
Engagement: Develop Effort and Persistence. Check in and provide each group with feedback that encourages collaboration and community.
Supports accessibility for: Social-Emotional Functioning

### Required Materials

Materials to Gather

### Required Preparation

• Each group of 2 needs a set of quadrilateral cards from the previous lesson.
• Each group of 2 will need a folder to hide the card during this activity.

### Launch

• Groups of 2
• “Now you’re going to play Mystery Quadrilateral with your partner. Re-read the directions for the game, then think about some words that may be helpful as you play.” (side, angle, right angle, equal, skinny, tall, slanted)
• 1 minute: quiet think time
• Share and record responses.
• Give each group a folder containing a set of the quadrilateral cards from the previous lesson.
• “How could you use the images of all the quadrilaterals on your paper as you play?” (They can help me think about questions I could ask. I could mark off quadrilaterals as I figure out that they're not the mystery quadrilateral.)
• Give students access to counters and let them know they can be used to cover shapes they want to cross out during the game.

### Activity

• “Play Mystery Quadrilateral with your partner. Be sure to take turns hiding the shape and guessing the shape.”
• 10–15 minutes: partner work time

### Student Facing

1. Partner A: Choose a shape from the group of quadrilaterals. Place it in the mystery quadrilateral folder without your partner seeing it.
2. Partner B: Ask up to 5 “yes” or “no” questions to identify the quadrilateral. Then guess which quadrilateral is the mystery quadrilateral.
4. Switch roles and play again.

### Activity Synthesis

• “What shapes were the easiest to figure out and why?” (W was easy because it was so different with one angle pointing in. X was easy because it was the only square resting on a side.)
• “What shapes were the most challenging to ask questions about and why?” (FF was challenging because none of the sides were the same length, and it was hard to get more information with “yes” or “no” questions. M and BB were hard to tell apart because they were so similar and it was hard to figure out what questions to ask.)

## Lesson Synthesis

### Lesson Synthesis

Display cards S, U, and X.

“Here are some quadrilaterals that are the same in some ways. What attributes would you use to describe how they’re different?” (I would focus on the number of sides that are the same length. I would focus on the number of right angles they have.)