Lesson 13

• Groups of 2
• Display the image.
• “What is an estimate that’s too high? Too low? About right?”
• 1 minute: quiet think time

• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.

• “How did you use the image or what you know about cantaloupe or other melons to help you make estimates?”
• Consider asking:
  • “Is anyone’s estimate less than 100 kilograms? Is anyone’s estimate greater than 500 kilograms?”
  • “Based on this discussion, does anyone want to revise their estimate?”
• Consider revealing that the actual weight of the giant cantaloupe is 344 kilograms.

This activity uses MLR4 Information Gap.

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

Here is an image of the cards for reference:

• Create a set of cards from the blackline master for each group of 2. 
• Keep set 1 separate from set 2.

• Groups of 2

• Display the task statement, which shows a diagram of the info gap structure.
• 1–2 minutes: quiet think time
• Read the steps of the routine aloud.
• “I will give you either a problem card or a data card. Silently read your card. Do not read or show your card to your partner.”
• Distribute cards.
• 1–2 minutes: quiet think time
• Remind students that after the person with the problem card asks for a piece of information the person with the data card should respond with “Why do you need to know (restate the information requested)?”

• 3–5 minutes: partner work time
• After students solve the first problem, distribute the next set of cards. Students switch roles and repeat the process with Problem Card 2 and Data Card 2.

• “What parts of the problem helped you make sense of the situation?”
• “Which quantities were important?”
• “Did anyone solve the problem in a different way than their partner?”

This activity uses MLR4 Information Gap.

In this activity, students solve addition and subtraction problems involving weight. Here is an image of the cards for reference:

• Create a set of cards from the blackline master for each group of 2. 
• Keep set 1 separate from set 2.

• Groups of 2

• “Let’s use the same information gap routine to solve new problems about another weigh-off.”
• “I will give you either a problem card or a data card. Silently read your card. Do not read or show your card to your partner.”
• Distribute cards.
• 1–2 minutes: quiet think time
• Remind students that after the person with the problem card asks for a piece of information the person with the data card should respond with “Why do you need to know (restate the information requested)?”

• 3–5 minutes: partner work time
• After students solve the first problem, distribute the next set of cards. Students switch roles and repeat the process with Problem Card 2 and Data Card 2.

• “What kinds of questions were the most useful to ask?”
• “Were there any questions you weren't sure how to answer?”
• “How did you represent your reasoning once you realized you needed to add (or subtract)?”