The overall results of the fourth U.S.A. Mathematical Olympiad are discussed. The names of the eight finalists are listed, as are the problems in the test. (SD)

Lines in the coordinatized plane which do not go through the origin can be designated by the ordered pair of intercepts. The enrichment unit described illustrates duality in mathematics. (SD)

Beginning with an analysis of the golden rectangle, the author shows how a series of problems for student investigation arise from queries concerning changes in conditions and analogous situations. (SD)

The subject of parallax can motivate learning related to measurement of lengths and angles as well as provide an introduction to trigonometric concepts. (SD)

A carpenter's square can be used to introduce students to an alternative method of performing geometric constructions. (SD)

Descriptions and pictures of apparatus for use in teaching measurement are accompanied by descriptions of typical uses of the materials. A list of names and addresses of suppliers is included. (SD)

Six different methods were used by students to solve the problem of finding the area of a given trapezoid. A seventh method used by textbooks is also discussed. (MP)

Discusses areas where minimal sculpture and geometrical play overlap. (GA)

Discusses how the International System (SI) abbreviations for numerical factors designated as prefixes may be treated in quantity calculus as free-standing algebraic symbols. Illustrative examples are also presented. (HM)

This problem solving strategy is illustrated by examples from the fields of algebra, trigonometry, geometry, and calculus. (MP)

Chemical bonding, for most simple complexes, is described in the Mulliken-Walsh Molecular Orbital (MO) theory. (CP)

Outlines mathematical topics of use to college geography students identifies teaching methods for mathematical techniques in geography at the University of Leeds; and discusses problem of providing students with a framework for synthesizing all content of geography education. For journal availability, see SO 506 593. (Author/AV)

Mathematical solutions to simple atomic structure problems involving (a) simple cubic, (b) body-centered cubic, and (c) face-centered cubic models are presented. (CP)

Construction of a series of 13 nested, regular tetrahedrons from 12 square sheets of paper without using geometric instruments, scissors, or glue is described. (MN)

A brief description of the operation of Euclid (a theorem-proving computer program written by the author) is given and directions to be taken in its continuing development are indicated. (MN)