"The power of two" is a Royal Institution (Ri) mathematics "master-class". It is a two-and-a half-hour interactive learning session, which, with varying degree of coverage and depth, has been run with students from Year 5 to Year 11, and for teachers. The master class focuses on an historical episode--the Josephus…

Procedures using calculators are described for determining the recurring sequence of digits in the decimal representation of numbers of the form 1/n. (MN)

After stating that almost any topic could be generalized, the author was challenged to generalize the topic of polyominoes. His response is presented in this article. (SD)

With the advent of computers and electronic calculators, the role of logarithms in the curriculum is changing. An intuitive approach to logarithms, stressing the notion of isomorphism, is discussed. (SD)

Relationships between the linear dimensions, surface area, and volume of parallelepipeds are examined. (SD)

Four categories of abuses are discussed: calculations, games and puzzles; mystical button pushing; and checking answers. Useful activities are illustrated for the categories of calculations, patterns, exploration, applications, and new content. (MP)

Using the overhead projector, or overlays on an original pattern, a variety of tessellations can be generated. Several illustrations are included. (SD)

Examples of CLOPAK Networks, an approach to covering the plane with symmetrically arranged, close-packed geometric shapes, are given. Implications for the place of networks in geometry instruction are discussed. (MN)

A problem concerning the generation of an array of numbers is posed. The author examines the use of this problem in several secondary-school and college classes. (SD)

Artistic configurations can be built using a rectangular array of points and number concepts or principles. (SD)

Use of graphs in studying greatest common divisors, least common multiples, and other concepts can illustrate patterns related to the definitions of these concepts. (SD)

Upper-level secondary students investigated square and triangular numbers and Pythagorean triples using computers. (SD)

A learning activity relating modular arithmetic to patterns of figures determined by points equally spaced around a circle is described. (SD)