Lesson 11

Center Day 2 (optional)

Warm-up: Number Talk: Make 100 (10 minutes)

Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for adding more than 2 two-digit numbers by making 100. The unit of cents also encourages students to consider how the value could be expressed using dollars, cents, or a combination of the two units. These understandings 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

  • Record answers and strategies.
  • Keep expressions and work displayed.
  • Repeat with each expression.

Student Facing

Find the value of each expression mentally.

  • \(80¢ + 20¢ + 37¢\)
  • \(80¢ + 20¢+ 37¢+ 42¢\)
  • \(75¢ + 37¢ + 25¢\)
  • \(75¢ + 80¢ + 25¢ + 20¢\)

Student Response

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Activity Synthesis

  • Revisit a student strategy that shows looking for a way to make 100 first and expresses the total in cents.
  • Consider asking:
    • “Who can restate _____'s reasoning in a different way?”
    • “Who can restate _____'s reasoning using dollars and cents?”

Activity 1: Introduce How Close?, Add to 1,000 (15 minutes)

Narrative

The purpose of this activity is for students to learn stage 4 of the How Close center. Students pick a given number of digit cards and then choose a subset of those to make an expression that yields a number as close as possible to the target number. Before playing, students remove the cards that show 10 and set them aside. Each student picks 8 cards and chooses 5 or 6 of them to create 2 three-digit numbers. Each student adds the numbers. The score for the round is the difference between each student's sum and 1,000. Students pick new cards so that they have 8 cards in their hands and then start the next round. The player with the lowest score after 10 rounds wins. 

Required Materials

Materials to Gather

Materials to Copy

  • How Close? Stage 4 Recording Sheet

Launch

  • Give each group a set of number cards and two copies of the blackline master. 
  • “We are going to learn a new way to play the How Close center.”
  • “Before you play, remove the cards that show 10 and set them aside.”
  • “Each person picks 8 cards and chooses 6 of them to create 2 three-digit numbers. Then add your three-digit numbers.”
  • “The score for the round is the difference between your sum and 1,000.”
  • “Then pick new cards so that you have 8 cards in your hand and then start the next round.”
  • “The player with the lowest score after 10 rounds wins.”
  • Answer any questions or play a round with the class as needed.

Activity

  • 10 minutes: partner work time

Activity Synthesis

  • “What strategies did you use to add the numbers?”

Activity 2: Introduce Five in a Row, Add Within 1,000 with Composing (25 minutes)

Narrative

The purpose of this activity is for students to learn stage 8 of the Five in a Row: Addition and Subtraction center. Students add within 1,000 with sums that require composing units when adding by place.

Then, students choose from any stage of previously introduced centers.

  • Five in a Row
  • How Close?

Required Materials

Materials to Gather

Materials to Copy

  • Five in a Row Addition and Subtraction Stage 8 Gameboard

Required Preparation

  • Each group of 2 needs 10 counters and 2 paper clips.
  • Gather materials from:
    • Five in a Row, Stages 7–8
    • How Close, Stage 4

Launch

  • Groups of 2
  • Give each group two paper clips, counters, and a gameboard.
  • “We are going to learn a new way to play the Five in a Row center. The center is the same as previous versions, but now you might need to compose new units when you add.”
  • “Take a minute to read the directions with your partner.”
  • Answer any questions. 
  • “Play this new version of Five in a Row with your partner.”

Activity

  • 10 minutes: partner work time
  • “Now you can choose another center. You can also continue playing Five in a Row.”
  • Display the center choices in the student book.
  • Invite students to work at the center of their choice. 
  • 10 minutes: center work time
  • If time, invite students to choose another center.

Student Facing

Choose a center.

Five a Row: Addition and Subtraction

Center activity. Five in a row.

How Close?

Center. How Close.

Activity Synthesis

  • “What did you like about the activities you worked on today?”

Lesson Synthesis

Lesson Synthesis

“When might you need to add numbers like the ones you worked with in these centers?”