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4th Grade Math – Classifying Triangles

Clip 7/18: Lesson: Classifying Triangles Part 1D

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  1. As the fourth-grade students continue their discussion about critiquing sample students’ work on classifying triangles, Hillary Lewis encourages them to explain and defend their thinking to other students in the class: “I think we're convinced that this triangle is obtuse, but I also had students who said they were convinced it was obtuse and put it here [under isosceles].

“What do you think about that? What did they understand, and what part got mixed up?” 

Students consider how the triangles can be compared differently when they are rotated.

Teacher Commentary

Hillary Lewis

The students engaged with each other well and used really nice — I don't know if they were sentence stems, but they would bond by saying, "To build on what so-and-so was saying …”

That was a really nice way to connect and show that they were listening to each other and building on each other. That was a gift, and I had nothing to do with that. Their classroom teacher did that, but because of the lesson — the way I designed the lesson — it needed that kind of conversation, and so it worked. It worked really well.