The purpose of this activity is for students to interpret and solve two-step problems involving length. Students represent and solve the problem in a way that makes sense to them.

Monitor for and select students with the following approaches to share in the Synthesis:

• Represent the initial length of ribbon and the actions in the story with tape diagrams or other clearly-labeled drawings or diagrams.
• Represent the initial length of ribbon and the actions in the story with base-ten diagrams or a series of equations to show subtraction. ( , )
• Represent the total length of ribbon that was cut off before subtracting it from the initial length of ribbon using diagrams or equations. ( , )

The approaches are sequenced from more concrete to more abstract ways to represent the quantities and actions in the story problem to help students make connections between different ways to make sense of and solve a two-step problem. Some students may use a combination of different representations (for example, a tape diagram to make sense of the story and base-ten diagrams to help with the calculations). Aim to elicit both key mathematical ideas and a variety of student voices, especially students who haven't shared recently.

• Invite previously selected students to share in the given order. Record or display their work for all to see.
• Connect students’ approaches by asking:
  • “How does each representation help you understand the problem?” (In the diagrams, they used labels to show what each part means. I can see how they used Lin's length of ribbon and the parts she cut off. In the equations, I can see the same numbers, but it's a little harder to tell what each part means. I can make sense of them by looking at the other diagrams people made.)
• Connect students’ approaches to the learning goal by asking:
  • “How was this story problem different from others we have solved?” (It had more steps. There were more things happening in the story. The ribbon wasn't cut just one time.)
  • “How did you keep track of what to do using diagrams or equations?” (I used labels to keep track of what was being subtracted in what order. I added words to my equations to help me remember what my equations were for. I reread the story to make sure my work matched what happened in the problem.)

The purpose of this activity is for students to represent and solve two-step story problems. Students begin the activity by looking at the first problem displayed, rather than in their books. At the end of the Launch, students open their books and work on the problems. In the Synthesis, students compare different ways they represent and solve the problems.

This activity uses MLR6 Three Reads. Advances: reading, listening, representing.

• Invite previously identified students to share their diagrams and equations for each part of the second problem.
• “How did _____ represent the problem with Andre’s ribbon? How does each representation show the story problem?”