Lesson 14

The purpose of this Number Talk is to elicit strategies and understandings students have for adding or subtracting 2. This routine does not use related problems to encourage students to use counting on or back or other mental strategies.

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

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

• “How can we add or subtract 2 quickly?” (You can think about it like counting up 2 or counting back 2.)

The purpose of this activity is for students to learn a new center activity called Sort and Display. This activity gives students an opportunity to sort items, represent how they sorted, and create questions that can be answered by their representation. Students sort items in any way they choose.

To connect this center to English language arts, students may sort and represent books. Students look at the cover of a book and choose three words or three images they think will show up most often in the story and explain why to their partner. Partners record these choices as initial categories. They read or look through the book together, explore their prediction, and decide together if they want to revise their categories based on what they read. On the second read, they collect and record data for their revised categories. Lastly, students create a representation based on their data and write two “how many?” questions that can be answered about the data.

• Make collections of 10–20 objects with up to three attributes by which to sort for each group.

• Groups of 2
• Give each group a collection of objects and two recording sheets.
• "We are going to learn a center called, Sort and Display, Any Way. First, you will work with your partner to sort your objects into two or three categories. Then, you will each show how you sorted on paper. When you are both done showing your sort, switch papers and ask each other questions about the sort that can be answered using your representations." 

• 15 minutes: center work time
• Monitor for students who make clearly labeled categories and represent how many objects are in each category.

• Display previously identified representation.
• “What questions can we ask about this sort that can be answered by this representation?”

The purpose of this activity is for students to choose from activities that focus on adding and subtracting within 10. Students choose from any stage of previously introduced centers and are encouraged to choose the center that will be most helpful for them at this time. 

• What’s Behind My Back
• Number Race
• Check it Off
• Five in a Row: Addition and Subtraction
• Find the Pair

• Gather materials from previous centers:
  • What’s Behind My Back, Stage 2
  • Number Race, Stage 3
  • Check it Off, Stages 1 and 2
  • Five in a Row: Addition and Subtraction, Stages 1 and 2
  • Find the Pair, Stage 2

• Groups of 2
• “Now 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

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

• “What is one thing you learned or got better at by working on the activity you chose?”