Presented is a example that shows why a certain technical lemma is necessary for a valid proof of Galois Theory. The usual proof of Galois' Theory is included as well as one using the lemma. (KR)

Presented is an alternate way to derive R from Taylor's Theorem without involving the (n + 1)st derivative of f. Included is the procedure for estimating the bounds of R. (KR)

Developed is a condition, expressed in terms of an index, that ensures that a quasinormal subgroup is normal. The arguments suggest a variety of exercises for a course in group theory or Galois theory. Included are the definitions, lemmas, and proofs. (KR)

Presented are activities that help students understand the idea of a vector field. Included are definitions, flow lines, tangential and normal components along curves, flux and work, field conservation, and differential equations. (KR)

Discussed are some applications of mathematics involved in actuarial science which may be taught in high school mathematics classes. Described are the importance of approximate solutions, multiple answers, and selling the solution to a problem. (CW)

Describes how Suzuki's methods of teaching young pupils to play the violin can be combined with Polya's ideas on problem solving to teach mathematics to elementary school pupils. Six references are listed. (YP)

Describes ways of finding the answer to a problem for the possible sum of the three-digit numbers without using the same number repeatedly. Describes the classroom applications of the problem. Provides a computer program to obtain the solutions of the problem. (YP)

Discusses the geometrical array of the keys on a calculator that can be turned into a problem-solving, problem-posing situation for the upper elementary or middle school classroom. Provides figures showing the arrays, including rows, diagonals, crosses, rhombi, angles, and squares. Lists seven references. (YP)

Analyzes fifth graders' approaches for solving the problem of the distance to the horizon. Describes determining the area bounded by the horizon. (YP)

Presented is a method for solving certain types of problems, with the goal of piquing students' interest in studying affine geometry, which underlines the method. (MNS)

A series of four activities are presented to enhance students' abilities to appreciate and use trigonometry as a tool in problem solving. Activities cover problems applying the law of sines, the law of cosines, and matching equivalent trigonometric expressions. A teacher's guide, worksheets, and answers are provided. (MDH)

Offers five suggestions to help students assess the reasonableness of their answers: (1) giving students a variety of problems; (2) facilitating students' discussions and interpretations of the problem conditions; (3) encouraging students to estimate answers before carrying out calculations; (4) encouraging students to ask whether their answers…

Presents an overview and discussion of some results of research on the use of graphing calculators organized into the following categories: (1) achievement studies, (2) conceptual understanding, (3) problem solving, (4) classroom dynamics, and (5) future research needed. (29 references) (MKR)

Describes the method that Archimedes utilized to calculate the volumes of spheres and other solids. The method found the volume of a sphere by comparing the mass of parallel slices of a sphere and a cone with that of a cylinder of known mass. (MDH)

Explains how critical thinking, communication, and estimation can be incorporated into an exciting problem-solving unit for first-grade students. Presents four related activities. (ASK)