Lesson 16

• Display the expression.
• “What do you know about \(3 + 2\)?”
• 1 minute: quiet think time

• Record responses.
• “How could we show \(3 + 2\)?”

• “3 and 2 is how many? How do you know?”

The purpose of this activity is for students to learn stage 2 of the Roll and Add center. Students roll to find 2 numbers, fill in an expression, and find the value of the expression. The purpose of the activity synthesis is to highlight different representations students used to find the value of the expressions, such as using fingers, using objects, and drawing pictures (MP2).

• Groups of 2
• Give each group of students a number mat and access to connecting cubes or two-color counters. Give each student a recording sheet.
• “We are going to learn a new way to play the Roll and Add center.”
• Display the recording sheet and the number mat.
• “I need to roll 2 cubes onto the mat. I’ll use the numbers to fill in an expression.”
• Demonstrate rolling 2 cubes and filling in an expression.
• “Now my partner and I need to work together to find the value of the expression. What can we do to find the value of the expressions?” (You can use your fingers. You can use objects. You can draw a picture.)
• Invite 2 students to demonstrate methods to find the value of the expression.
• Demonstrate writing the total on the line.
• “Work with your partner to roll 2 cubes, fill in an expression, and find the value of the expression. Take turns rolling.”

• 7 minutes: partner work time
• Monitor for students who use the methods listed in the activity narrative to find the value of expressions.

• Invite a student who used their fingers to find the value an expression to share.
• Invite a student who used objects to find the value of an expression to share.
• Invite a student who drew a picture to find the value of an expression to share.
• After each student shares, ask students where they see each number in the expression in the representation.

The purpose of this activity is for students to find the value of addition and subtraction expressions.

• Groups of 2
• Give students access to two-color counters or connecting cubes.
• Write and display \(4 - 2\).
• “Find the value of \(4 - 2\).”
• 1 minute: independent work time
• “Show your partner how you found the value of \(4 - 2\). What is the same and what is different about how you found the value of the expression?” (We both showed 4 things first and we both took away 2 things. One of us put down 2 fingers and one took off 2 counters.)
• 1 minute: partner discussion
• Share responses.
• “\(4 - 2\) is 2.”
• “Work with your partner to find the value of each expression. Write your answers on the line next to each expression.”

• 6 minutes: partner work time

• “What do you know about this expression?”
• “Can you use these connecting cubes to show the expression? How can the cubes help you find the value of the expression?”

• Display answers.
• “How can our fingers help us find the value of an expression?”
• “How can counters help us find the value of an expression?”
• “How can drawing a picture help us find the value of an expression?”

The purpose of this activity is for students to choose from activities that offer practice with addition and subtraction story problems and expressions, as well as writing numbers.

• Roll and Add
• Shake and Spill
• Number Race
• Math Stories

• Gather materials from: 
  • Roll and Add, Stages 1 and 2
  • Shake and Spill, Stages 1-3
  • Number Race, Stage 1
  • Math Stories, Stages 1 and 2

• “Today 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 something that used to be challenging for you that you’ve gotten better at? What did you do to help yourself improve?”