We consider here a number of ideas for the classroom or lecture theatre associated with the mensuration of solids. In particular, the volumes of various tetrahedra are obtained in an indirect manner (by way of prisms and square-based pyramids). This activity develops problem-solving skills, spatial visualization and a from-first-principles…

Fermi problems are problems which, due to their difficulty, can be satisfactorily solved by being broken down into smaller pieces that are solved separately. In this article, we present different sequences of activities involving Fermi problems that can be carried out in Secondary School classes. The aim of these activities is to discuss…

Revisits and discusses the polar bear problem that was published in the March 1997 issue. The problem concerns a riddle: If you walk one mile south, one mile east, and one mile north, and end up in the same spot as you started, what kind of bear would you see? (ASK)

Describes the Six Circle problem which consists of the numbers 1-6, six circles, and asks whether it is possible to put the numbers in the circles--which are configured in a triangle--so that the sums of the three numbers on either side are the same. (NB)

Presents a game in which if player is playing a match of this game with an opponent, at each step in the game he has to decide whether to continue or to stop. Helps students to develop a strategy for making such a decision based on the expected gain and related probabilities. (Author/ASK)