Lesson

# Clip 12/16: Adding and Subtracting Fractions Using a Line Plot Lesson Part 2D

## Overview

Mallory’s 5th-grade students orient themselves to problem three of the task, as the students discuss and debate their ideas about how to solve the problem. They clarify their terms: “I think we’re adding.” “Adding what? All the amounts together?” “I think so, that’s what it says.” They also check and revise their thinking as needed: “Eight over one? That didn’t work.” “I think we messed up.” “That didn’t work. All right, now I’m stuck, I thought that would work, but it did not at all.” “Hey, it’s worth trying.” Mallory circulates among the groups but refrains from giving students the answers: “That’s a conversation that you guys can have together. I’m not going to say yes or no.”

## Teacher Commentary

The other thing that was really awesome that came out was if the total was changed, what fractional amounts could you add to the line plot? That was a struggle for them. There's all these open-ended questions. There's a lot of opportunities for several right answers, and they were looking for one. A lot of great questions that accumulated from that. So that was a depth-of-knowledge three question that just really blew their minds as well.