Using a dog's paw as a basis for numerical representation, sixth grade students explored how to count and regroup using the dog's four digital pads. Teachers can connect these base-4 explorations to the conceptual meaning of place value and regrouping using base-10.

Results from a project conducted in Mexico are discussed, in which a group of 17 indigenous teachers analyzed the numeration systems of their first language. The main goal of the project is to develop resources that help teachers in supporting students' understanding of the systems. In the first phase of the project, the central organizing ideas…

The leftist number system consists of numbers with decimal digits arranged in strings to the left, instead of to the right. This system fails to be a field only because it contains zerodivisors. The same construction with prime base yields the p-adic numbers.

The general purpose of this article is to shed some light on the understanding of real numbers, particularly with regard to two issues: the real number as the limit of a sequence of rational numbers and the development of irrational numbers as a continued fraction. By generalizing the expression of the golden ratio in the form of the limit of two…

An interesting number system is developed in the context of an encounter with alien culture. The resulting system has intriguing parallels and contrasts with our real number system.

"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…

The method used by Cantor to demonstrate the uncountability of the real numbers is applied to a proof showing that the set of natural numbers is uncountable; the error in the argument is discussed. (DT)

The problem of getting a correct result when a fraction is reduced by cancelling a digit which appears in both the numerator and the denominator is extended from the base ten situation to any number base. (DT)

All the familiar numbers (rationals, algebraic numbers and a few transcendental numbers) have measure zero. (MM)

This study traces the development of nondecimal numeration from the 16th century to the present. The first six chapters detail the contributions of mathematicians as well as people from other fields. Applications to computers are covered in one chapter, while another chapter discusses the coverage of numeration systems in college textbooks for…