Lesson 13

The purpose of this Number Talk is to elicit understandings students have for adding and subtracting within 20 using the strategy of making a ten.

• 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.

• “Did anyone approach the problem in a different way?”

The purpose of this activity is for students to choose from activities that offer practice working with tens and ones. Students choose from any stage of previously introduced centers.

• Grab and Count
• Five in a Row
• Check It Off

• Gather materials from previous centers:
  • Grab and Count, Stage 2
  • Five in a Row, Stages 1–4
  • Check It Off, Stages 1–3

• Groups of 2
• “Now you 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

• “Han is playing Check It Off. He picks the numbers 70 and 20. What numbers could he check off?” (50 or 90)

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 20. Students choose from any stage of previously introduced centers.

• How Close?
• Number Puzzles
• Shake and Spill

• Gather materials from previous centers:
  • How Close, Stages 1 and 2
  • Number Puzzles, Stages 1 and 2
  • Shake and Spill, Stages 3–5

• Groups of 2
• “Now you 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

• Display 8, 4, 1, 7, 5.
• “Priya is playing How Close. Which three numbers should she choose to get close to 20?”