Lesson 11

The purpose of this What Do You Know About _____? is to invite students to share what they know about story problems. Monitor for student comments regarding the types of story problems they know about and the methods they use to understand and represent story problems.

• Display the question.
• “What do you know about story problems?”
• 1 minute: quiet think time

• Record responses. 
• As needed, ask:
  • “What are some ways you can show what happens in a story problem?”

• “Today we are going to solve different types of story problems and share the different ways we represent and solve them.”

The purpose of this activity is for students to solve a story problem in a way that makes sense to them. Students solve a Compare, Difference Unknown problem within 50 that requires composing or decomposing a ten if students add or subtract by place. During the synthesis, students describe and compare how they used tools, diagrams, and equations in different ways to make sense of and solve the problem (MP2, MP3, MP5).

Students may represent or solve the problem with any method that makes sense to them. Monitor and select students with the following methods to share during the synthesis:

• use connecting cubes or base-ten blocks to represent the problem as a comparison
• use a tape diagram to represent the problem
• use base-ten blocks to show adding or subtracting by place
• use a base-ten diagram to show adding or subtracting by place
• use an equation(s) to show adding or subtracting by place

• Groups of 2
• Give students access to connecting cubes and base-ten blocks.
• “Has anyone ever seen seeds? Where have you seen them? Where can they be found?”
• Share responses.

• “Diego and Jada gathered seeds to plant. You can use the connecting cubes, base-ten blocks, or other representations to help make sense of the problem and solve it. Be prepared to explain your thinking.”
• 6 minutes: independent work time
• As students work, consider asking:
  • “What do you need to find to answer the question? How do you know?”
  • “How did you show Diego’s seeds?”
  • “How did you show Jada’s seeds?”
  • “How will you find the difference?”
• “Now compare your method with your partner. How are your methods the same? How are they different?”
• 2 minutes: partner discussion

If students find the sum of Diego and Jada’s seeds, consider asking:

• “What does the story problem ask you to find?”
• “How does your work show how many more seeds Diego used?”
• “How could you use your tools or a diagram to compare Diego and Jada’s seeds?”

• Invite previously identified students to share their methods in the given order. 
• “How are the diagrams the same? How are they different?” (The diagrams all show Diego’s and Jada’s seeds. Some diagrams show the problem and help you see the bigger amount, the smaller amount, and the difference. Some diagrams show how we added and subtracted tens and ones.)

The purpose of this activity is for students to solve different types of story problems within 50 that may require composing or decomposing a ten when adding or subtracting by place. Students are encouraged to solve the story problems in a way that makes sense to them. The synthesis focuses on sharing the ways students made sense of and solve a Compare, Smaller Unknown problem.

Monitor for a variety of different ways students use drawings, diagrams, or equations to make sense of or solve the problems for sharing in the lesson synthesis. Look and listen for examples of ways students make sense of what they need to find, such as a tape diagram or base-ten blocks, before they use methods to calculate unknown values (MP1).

• Groups of 2
• Give students access to base-ten blocks.

• “Work with your partner to make sense of each story problem and solve it. Show your thinking using drawings, numbers, or words.”
• 8 minutes: partner work time
• Monitor for different ways students use labels and diagrams to make sense of the last problem.

If students attempt to compare the quantities in every problem or use representations that do not match the situation, consider asking:

• “What is happening in this story?”
• “How could you work together to act out the story?”

• Invite previously identified students to share their diagrams and labels.
• If students do not use tape diagrams to show the last problem, but represent their thinking using visually similar ways (for example, placing a row of base-ten blocks above another row of base-ten blocks), record these methods using a tape diagram.
• Consider asking:
  • “How did your representation help you understand the story problem?” (It helped me show what was happening with the seeds in the story. It helped me show the different groups of seeds and what I needed to find.)
  • “How did your representation help you solve the story problem?” (It helped me see what I needed to find and helped me think about whether I wanted to add or subtract to find the unknown value.)