Don Argo develops the idea of definitions as the foundation of mathematical thinking, humorously illustrating this with his “Male Chauvinist Pig Club” example. He reviews commutative and associative properties, introduces identity elements, and distinguishes between additive and multiplicative inverses, showing how inverses produce identity elements. The lesson concludes with absolute value, explained through piecewise definitions, junctions, and careful use of mathematical language.

Don Argo develops the idea of definitions as the foundation of mathematical thinking, humorously illustrating this with his “Male Chauvinist Pig Club” example. He reviews commutative and associative properties, introduces identity elements, and distinguishes between additive and multiplicative inverses, showing how inverses produce identity elements. The lesson concludes with absolute value, explained through piecewise definitions, junctions, and careful use of mathematical language.