Tests for divisibility in bases 2 through 10 are presented. Two strategies used by a group of fourth-year students are described. (MNS)

Number bases other than ten can be introduced effectively by presenting fictional civilizations which use them. (SD)

The system of International Standard Book Numbers uses a check code based on modular arithmetic. This system, the use of a simple machine to compute check digits, and related classroom activities are described. (SD)

Activity questions based on the prime factorization of numbers can be answered by reference to the lattice structure of factors. (SD)

Suggests that there is sufficient interest in the changing arrangements of stars in the flag of the United States over the years to introduce a mathematical investigation into the various possible patterns of stars. (Author/JJK)

A general method and a variant for divisibility are presented, with specific examples. (MNS)

Two algorithms are developed for finding the square roots of numbers. One is based on the rule that x square is the sum of the first x odd numbers; the other is algebraic. (MP)

A number of activities are suggested that provide motivation and increases the confidence of students involved in practicing numerical skills. (MP)

Describes public key cryptography, also known as RSA, which is a system using two keys, one used to put a message into cipher and another used to decipher the message. Presents examples using small prime numbers. (MKR)

Exploring the strategies used in simple games for two players is discussed. Six games are briefly described, followed by suggestions for analyzing them. (MNS)

Graphical representations of modular arithmetic multiplication tables and of equations in modular systems are investigated. (DT)

Activities with triangular, square, pentagonal, hexagonal, and octagonal numbers are briefly discussed. (MNS)

Advocated is developing intuitive ideas of limits whenever the opportunity arises in elementary mathematics. Examples are given for geometry, fractions, sequences and series, areas, probability, graphing, and the golden section. (MNS)

Three games in which the calculator plays an important facilitating role are presented. It promotes a "guess then adjust your guess" strategy. The games are described within the context of elementary, junior high, and secondary classrooms. (MNS)

Exercises are used when beginning work with calculators to help pupils think about what they are doing. Four worksheets are included, with discussion of their objectives. (MNS)