Twenty years ago when the author was student teaching, he quickly learned what geometry teachers and researchers (e.g., Senk 1985) have long known: High school geometry students struggle with proof. Throughout his career, he has tried to create instructional materials to make proof more accessible to his students. From field-testing materials with…

Presents a developmental approach to teaching programing at all educational levels which stresses concepts rather than syntax; provides motivation, relevant examples, and activities; proceeds from concrete to pictorial to abstract according to age and experience of learners; and utilizes increasingly complex activities building upon and extending…

This article presents the "concrete semiconcrete abstract" (CSA) teaching sequence for teaching basic math skills to students with and without learning disabilities. Guidelines include providing a minimum of nine instructional lessons (three at each level), each with four lesson steps. Validation of the CSA sequence and lesson format with 15…