In the past we developed a lesson for the introduction of quadratic functions using a set of examples and non-examples of quadratics. After sharing that lesson we received many requests for additional examples/non-examples lessons as a way to kick off key mathematical concepts. Thus, at the 2019 Missouri Council of Teachers of Mathematics conference we shared two additional sets of examples and non-examples:

Examples and Non-Examples of Prisms
Examples and Non-Examples of Trinomials

We also described our process for creating these sets of examples and non-examples. It’s actually quite fun and can lead to good conversations and conceptual understanding of any important mathematical object. SEE PRESENTATION SLIDES

At MCTM 2019, the TMTG team also presented on problem reversals.