## Reflection: Joy Who's a Widget? Making Sense of Definitions - Section 1: Launch: Who's a Widget? (How to Write Good Definitions)

To launch this task, I made a decision to give students a concrete example that would show the two components of good definitions: classification and differentiation.  By modeling this idea with an example for a strawberry--a red fruit that is juicy and has seeds on its surface--I was able to give my students a clear idea of what I was looking for.

When we shared out definitions to test by looking for counterexamples, I try to create safety for the presenting group by saying things like, “counterexamples are the best for revealing holes in our definitions” or “counterexamples help us to see opportunities to improve our definitions.”  Additionally, as students explained their counterexample, I tried to control the tone and energy in the room (students LOVE this activity!!!) by telling them that they aren’t trying to “win” or “show another group why they are wrong,” but instead, revealing a consideration the writing group would need to make for their definition.

Making Definitions Concrete
Joy: Making Definitions Concrete

# Who's a Widget? Making Sense of Definitions

Unit 2: Introducing Geometry
Lesson 2 of 8

## Big Idea: Students will write precise definitions based on examples and non-examples and test these definitions by looking for counterexamples.

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Standards:
Subject(s):
Math, Geometry, deductive reasoning, definition, basic properties
70 minutes

### Jessica Uy

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