The purpose of this activity is for students to match expressions to base-ten diagrams. Students then choose 2 of the expressions to find the value of, using any method that makes sense to them. Some of the expressions do not require composing or decomposing a ten. A matching task gives students opportunities to analyze expressions and diagrams closely to look for and make sense of structure (MP7).

• Invite previously selected students to share how they chose expressions to solve.
• Consider asking:
  • “Which expressions did you choose to solve? Why?” (I chose because it was easy for me. I knew that I could just add the ones and then add the tens.)
  • “How could you tell if you would need to compose or decompose a ten?” (I could see that , so I knew I wouldn’t need to compose a ten.)

The purpose of this activity is for students to add and subtract within 100 using the methods that make sense to them. Throughout the activity, students share their methods for adding and subtracting and compare their methods with others (MP3).

This activity uses MLR7 Compare and Connect. Advances: representing, conversing

• “How are the methods represented differently in each display?”
• “How did each group find the same value when they used such different methods?”

• 5–7 minutes: Gallery Walk
• “What was the same about how _____ found the value and _____ found the value?” (In the first problem, _____ and _____ both added the ones and added the tens and then combined the two sums. , , )
• “What is different about how _____ represented their thinking and ______ represented theirs?” ( _____ used a diagram and crossed out the ones and then decomposed a ten. Then _____ crossed out the rest of the ones and the tens. _____ wrote equations to show each step.)