From now on we will feature a different book every month that is likely to be of interest to secondary teachers wanting to know more about mathematics. We have made the decision to use this feature to bring older books…
Originating author is Christiane Rousseau. Mathematics offers tools for classifying objects. But is that of any practical use? More than we can imagine at first sight… It could allow us to conclude that a knot cannot be unknotted without cutting…
Starting in January, we began a “Site of the Month” feature. February’s site of the month is dedicated to: NRICH. NRICH is a team of mathematics teachers, who aim to enrich the mathematical experience for all. They provide engaging activities…
Originating author is João Pimentel Nunes The Hairy Ball Theorem is from topology, that part of mathematics that is concerned with the form of spaces. For the most part, this result came from work at the end of the 19th…
Each month, we will feature a site that we feel is relevant to aims of the Klein Project. The first site of the month is dedicated to: Mathematics of Planet Earth (MPE). MPE is an initiative of mathematical science organizations…
Originating author is Graeme Cohen. Of all the familiar functions, such as trigonometric, exponential and logarithmic functions, surely the simplest to evaluate are polynomial functions. The purposes of this article are, first, to introduce the concept of a power series,…
Originating authors are David Mumford and Christiane Rousseau. Foreword: This vignette is more difficult than others. However, in a few pages, it tells you how to explain in simple terms one of the most difficult open problems at the beginning…
Originating authors are Graeme L. Cohen (University of Technology, Sydney), Steven Galbraith (University of Auckland) and Edoardo Persichetti (University of Auckland). How can we safely send our credit card details over the internet, or using a mobile phone, when others…
Originating author is William Mc Callum. If two triangles have the same area and the same perimeter, are they necessarily congruent? It turns out that the answer is no. For example, the triangle with sides and has the same area…
（王婷 译 李建华 校 北京师范大学数学科学学院）