This article outlines a theoretical model for teaching elementary mathematical concepts that we have developed over the past 10 years. We begin with general ideas about the abstraction process and differentiate between abstract-general and abstract-apart concepts. A 4-phase model of teaching, called Teaching for Abstraction, is then proposed that is explicitly designed to promote abstract-general learning. Studies investigating the model with 4 different topics (angles, decimals, percentages, and ratios) are reported, and the 4 phases are further elucidated. The article concludes with a discussion of the effectiveness of the model and its applicability to other mathematical concepts.