The purpose of this activity is to introduce students to the structure of the MLR4 Information Gap routine. This routine facilitates meaningful interactions by positioning some students as holders of information that is needed by other students.

Tell students that first, a demonstration will be conducted, in which the whole class plays the role of the person with the problem card. Explain to students that it is the job of the person with the problem card (in this case, the whole class) to think about what information they need to answer the question.

For each question that is asked, students are expected to explain what they will do with the information, by responding to the question, “Why do you need to know _____ [that piece of information]?” If the problem card person asks for information that is not on the data card (including the answer), then the data card person must respond with, “I don’t have that information.”

Once students have enough information, they solve the problem independently.

The Info Gap routine requires students to make sense of problems by determining and then asking for the information needed to solve them. This may take several rounds of discussion if their first requests do not yield the information they need (MP1).

• Invite 1–2 students to share how they solved the problem.
• “What were the important quantities to know to solve this problem?”
• “Which questions that you asked helped you find out those quantities?”

The Info Gap routine in this activity, prompts students to compare lengths of time given in different units. To make comparisons, students need to convert one unit into another or otherwise reason about equivalent amounts. They also need to relate quantities in multiplicative terms—to think of a quantity as a certain number of times as much as another quantity.

The Info Gap structure requires students to make sense of problems by determining, and then asking for, the information necessary to solve them. This may take several rounds of discussion if their first requests do not yield the information they need (MP1). It also allows students to refine the language they use and to ask increasingly more precise questions until they get the information they need (MP6).

• “What were the important quantities to know to solve the first problem? What about in the second problem?”
• “Did anyone solve the problem in a different way than their partner?”
• “How did you compare 9 hours and 90 minutes?”
• “How did you find out if Noah spends more than or less than 4 hours with his family on a weekend day?”

This optional activity invites students to apply their knowledge of pounds and ounces and multiplicative reasoning to solve a puzzle about the quantities of ingredients on a shopping list. To solve the puzzle, students need to express pounds as ounces and reason deductively.

As they work to eliminate possibilities, draw conclusions, and explain their thinking to others, students practice constructing logical arguments (MP3).

• Discuss the order in which students completed the unknown values. Ask questions such as:
  • “Which was the first ingredient amount you figured out? Was there a reason you started with that item?” Rice noodles, because it is lightest and pound is very light.)
  • “Which ingredient amount did you figure out next?” (Brown rice, because it is 20 times the weight of rice noodles.)
  • “Was there a point at which you saw multiple possibilities? How did you decide what to do?” (Any of the items could have been pound, but if the heaviest amount was pound, the other ingredients would be very small and not make much sense.)
  • “How did you find the weight of the heaviest item? How did you know which it was?” (I found .)