This study examines the effects of using different classes of ratios on adolescent performance on proportionality problems. Problems of the form a/b = c/x varied on four dimensions: size of a/b, equality or inequality of b and c, complex or simple fractions, and form of the test. Tests consisted of six proportionality problems involving sizes of…

This paper reports further on the study described in SE 019 717. Correlational data relating success on proportionality tasks to understanding of related concepts and processes are presented. The five correlative tests involve (1) reducing fractions, (2) multiplying fractions, (3) facility with fractions, (4) inverse relations, and (5) more…

On the basis of studies reported elsewhere (SE 019 717 and 719) the author discusses the implications of research on cognitive development for teachers whose subjects involve an understanding of proportionality. Several common methods of teaching chemistry students to use proportionality in chemical problems are described. Research on the…