Lesson 3

The purpose of this Choral Count is to invite students to practice counting by 2 and notice patterns in the count. Although students are not required by the standard to count by 2, this warm-up allows students to pay attention to patterns that will be helpful later in the lesson when students determine and justify whether a group of objects is even or odd.

• “Count by 2, starting at 2.”
• Record as students count.
• Stop counting and recording at 40.

• “What patterns do you see?”
• 1–2 minutes: quiet think time
• Record responses.

• “Who can restate the pattern in different words?”

The purpose of this activity is for students to determine whether a group of objects is even or odd. The context and the structure of the images allow students to look for ways to make 2 equal groups (1 yellow group and 1 blue group) or make pairs (1 yellow and 1 blue). Students are given access to yellow and blue crayons or colored pencils, but are not required to color the designs. Some students might be able to answer all of the questions without coloring.

Students who color the images or pair them in an organized fashion are determining whether there are an even or odd number by finding a visual structure in the collection of images (MP7).

• Each group of 2 needs access to counters and blue and yellow crayons or colored pencils.

• Groups of 2
• Give students access to counters and yellow and blue crayons or colored pencils.
• Display or draw:

  

  

• “What do you notice? What do you wonder?” (There are 6 circles. There are 3 yellow circles and 3 blue circles. I wonder if it’s a pattern - yellow, blue, yellow, blue, yellow, blue)
• 30 seconds: quiet think time
• 1 minute: partner discussion
• Share responses.

• “Han wants to color other designs so that he has the same number of yellow circles and blue circles.”
• “Use the design, symbols, or your own representations to figure out which designs Han should pick. Be ready to share your thinking with your partner.”
• 5 minutes: independent work time
• Monitor for students who:
  • color or label with color names
  • find 2 equal groups
  • pair shapes
• 3 minutes: partner discussion

If students match or draw designs with an odd number of shapes, consider asking:

• “What must be true about the number of yellow and blue shapes after Han colors a design?”
• “How do you know this design will match what Han is looking for?”

• “Which designs have an even number of shapes? Explain how you know.” (A and D because there is an equal number of yellow and blue. A and D because every yellow circle can be paired with a blue circle.)
• “Does Priya’s design have an even or odd number of shapes? Explain how you know.” (Even. You could make 2 equal groups of shapes. You could pair each circle with another shape.)

The purpose of this activity is for students to determine and justify why a representation shows an even or odd number of objects. They connect equations to visual representations and use them to reason about even and odd numbers (MP2). Although some images may be designed to elicit reasoning about 2 equal groups or pairs of objects, students should be encouraged to explain their thinking using the method that makes the most sense to them.

This activity uses MLR8 Discussion Supports. Advances: speaking, listening, conversing

• Create a set of cards from the blackline master for each group of 2.

• Groups of 2
• Give each group a set of cards.

• “When it’s your turn, pick a card. Decide whether it shows an even or odd number of objects. Then, explain your choice to your partner. Place each card into the even group or the odd group.”
• “If your partner agrees, continue sorting your cards.”
• “If your partner disagrees, listen to their explanations and make a decision together about how to sort the card.”

MLR8 Discussion Supports

• Display sentence frames to support small-group discussion:
  • “This card shows an even number because . . .”
  • “This card shows an odd number because . . .”
  • “I agree because . . .”
  • “I disagree because . . .”
• 12 minutes: partner work time
• Monitor for a variety of ways students explain how they know a representation shows even or odd for sharing in the lesson synthesis.

• Invite previously identified students to share a match that shows an even number of objects.
• “How do these cards show that the number of objects is even?”
• Invite previously identified students to share a match that shows an odd number of objects.
• “How do these cards show that the number of objects is odd?”