This column contains brief notes on an unusual binary operation; calculating compound interest rates; costing a book; the m-th root of a positive integer; and an arithmetical puzzle. (MM)

Problems involving divisibility, the ten coin triangle, five times a week with 4 D, a nomogram for the lens formula, the box and ladder problem, chains of circles, tessellating hexagons, topological woggles, and numbers of triangles are discussed. (CT)

The authors present an enrichment topic appropriate for use in grade 12. A mathematical system is defined using integer 3-tuples and it is shown that this system is a field isomorphic to the rational numbers. The unit is useful for illustrating the abstract nature of mathematics. (CT)

How to play the medieval game of Rithmomachia, the battle of rhythms, is described. It is really eight games played with one set of rules. (MNS)

Describes strategies for developing mathematical language and concepts in nursery school children in Nigeria using English as a second language, including use of sand, water, wooden blocks, and dramatic play in the classroom shop. Suggests that through these methods a verbal foundation is laid for mathematical understanding. (Author/BK)

Four unusual mathematics problems with interesting routes to solution are presented. A general method of solution to problems of this type is proposed. (MP)

A short history of the evolution of the calendar is given. Calculations with various time periods are given. (MK)