Aiming to enhance understanding of visual obstacles inherent in two-dimensional (2-D) sketches used in high school spatial geometry instruction, we propose a measure of visual difficulty based on two attributes of the sketches: potentially misleading geometrical information (PMI) and potentially helpful geometrical information (PHI). The…

Demonstrates how research-based knowledge of students' incompatible solutions to various representations of the same problem could be used to raise their awareness of inconsistencies in their reasoning. Reports that students' decisions as to whether two given infinite sets have the same number of elements depend on the specific representation of…

Defines spatial structuring as the mental operation of constructing an organization or form for an object/set of objects. Examines in detail students' structuring and enumeration of two-dimensional rectangular arrays of squares. Concludes that many students do not see row-by-column structure. Describes various levels of sophistication in students'…

Explores the role of spatial orientation skill in the solution of mathematics problems. Reports the role of estimating the approximate magnitude of a figure; demonstrating the flexibility to change; adding marks to show relationships; moving or assessing the size and shape of figure; and getting the correct answer. (YP)

Mathematics educators frequently recommend that students use strategies for measurement estimation, such as the reference point or benchmark strategy; however, little is known about the effects of using this strategy on estimation accuracy or representations of standard measurement units. One reason for the paucity of research in this area is that…

Examines preschool children's understanding of the mathematical significance of unit size through problems that involve making judgments about the number of larger objects versus the number of smaller objects. Elicits children's judgments about the effects of object size both before and after the presentation of a series of demonstration trials.…

Investigates gender differences and the role of spatial visualization in problem solving in high school geometry. Reports that, whereas males and females differed in spatial visualization and in their performance, they did not differ in logical reasoning ability or in their use of geometric problem-solving strategies. (Author)