Lesson 15

The purpose of an Estimation Exploration is for students to practice the skill of estimating a reasonable answer based on experience and known information. In the synthesis it is important to discuss things the writer had to pay attention to when they designed this activity.

• 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.

• “What did the writer of this activity have to pay attention to when they designed this activity?” (Something in the image that shows how many things fit in one line or a small part of the image. An image where it is hard to see or count the exact number of objects.)
• Record and display responses for all to see.

The purpose of this activity is for students to work in groups to create an Estimation Exploration activity that focuses on multi-digit multiplication. Students use an object from the classroom, their own drawing, or find an image in a book or from another source and fill in how other students might estimate the quantity of items.

• Groups of 3 or 4
• “Work with your group to create an Estimation Exploration activity about counting a large number of objects.”

• 15 minutes: small-group work time

• “What questions do you still have about creating your Estimation Exploration?” (What if there are so many things that it's hard to estimate? Like people in a stadium or leaves on a tree or trees in a forest? What if there are not so many things and estimating is simpler, like the number of kids in a classroom or the number of pattern blocks in a container?)
• Give students a few minutes to make adjustments based on questions, if needed.

The purpose of this activity is for students to facilitate the Estimation Exploration they created in the previous activity for another group in the class. Each group should be paired with another group and they will take turns facilitating their Estimation Exploration for the other group. If time allows, students could facilitate their Estimation Exploration with more than 1 group.

• Groups of 3 or 4
• Give each group a piece of chart paper and a marker to record responses.
• “Pair up with another group in the class. Each group will present their Estimation Exploration.”

• 10–12 minutes: small-group work time
• Remind students to switch roles halfway through the time allowed.

• “What did you learn as you presented your Estimation Exploration?” (I learned that ranges of estimates might be bigger than you expect. I learned that it’s important to understand the size of the items you are trying to estimate or be familiar with it, otherwise you cannot make good estimates.)