The three target articles presented in this special issue converged on an emerging theme: the importance of spatial proportional reasoning. They suggest that the ability to map between symbolic fractions (like 1/5) and nonsymbolic, spatial representations of their sizes or "magnitudes" may be especially important for building robust…

The ability of some individuals with mental retardation to identify prime numbers despite their lack of necessary arithmetical skills is discussed. The article suggests that a distinction between prime and nonprime numbers can be made by utilizing the tendency of visual perception to be symmetrically organized. (Author/DB)

Discusses students' inability to make the connection between manipulative materials and pencil-and-paper calculations in mathematics instruction. Outlines the development of mathematical ideas through the concrete, representational, and abstract phases of instruction. An annotated bibliography listing teacher resources for representational-level…

The development of an instructional model for teaching formal mathematical concepts (probability concepts) to disadvantaged high school students through computer programming and some results from a field test are described in this document. The instructional model takes into account both learner characteristics (cognitive, affective, and…