A history of perfect numbers is presented, which briefly covers the 27 values known at this time. (MP)

Presents evidence that human infants possess a mechanism for determining and representing small numbers of entities and procedures for operating on these representations to extract numerical relationships between them. Presents a model for this mechanism and discusses its relation to later numerical knowledge. Contains 42 references. (MKR)

Presents activities to cultivate the tendency to see special qualities in numbers that can be played on certain calendar days. Includes games on the constant of the day, Fibonacci and golden ratio dates, primes, powers, December 25, and the day of the year. (ASK)

Discusses the use of MAPLE, a computer algebra system, to find Chinese pseudoprimes. (MKR)

In this study, we use children's prior knowledge to support their development of cardinality understanding, based on Bermejo's (1996) model of cardinality understanding and on the distinction between cardinality (the number of items in a set is represented by a number-word) and the cardinality principle (the last number-word used in counting…

Working memory is the cognitive ability to hold a discrete amount of information in mind in an accessible state for utilization in mental tasks. This cognitive ability is impaired in many clinical populations. There have been a number of theoretical shifts in the way that working memory is conceptualized and assessed in the experimental…

The overreliance on linear methods in students' reasoning and problem solving has been documented and discussed by several scholars in the field. So far, however, there have been no attempts to assemble the evidence and to analyze it is a systematic way. This article provides an overview and a conceptual analysis of students' tendency to use…

I describe how data pooling and data visualization can be employed in the first-semester general chemistry laboratory to introduce core statistical concepts such as central tendency and dispersion of a data set. The pooled data are plotted as a 1-D scatterplot, a purpose-designed number line through which statistical features of the data are…

This article focuses on spontaneous and progressive knowledge building in ''the arithmetic of the child.'' The aim is to investigate variations in the behavior patterns of eight pupils attending a school for the intellectually disabled. The study is based on the epistemology of radical constructivism and the methodology of multiple clinical…

Preschoolers made numerical comparisons between sets with varying degrees of shared surface similarity. When surface similarity was pitted against numerical equivalence (i.e., crossmapping), children made fewer number matches than when surface similarity was neutral (i.e, all sets contained the same objects). Only children who understood the…

Catalan numbers are defined by combinatorial properties, in numerous situations. Here, an integral representation for these Catalan numbers is computed.

An interesting class of purely pandiagonal, i.e. non-magic, whole number (integer) squares of orders (row/column dimension) of the powers of two which are related to Gray codes and square Karnaugh maps has been identified. Treated as matrices these squares possess just two non-zero eigenvalues. The construction of these squares has been automated…

"Contemporary Debates in Childhood Education and Development" is a unique resource and reference work that brings together leading international researchers and thinkers, with divergent points of view, to discuss contemporary problems and questions in childhood education and developmental psychology. Through an innovative format whereby leading…

This article explores elementary school teachers' mathematical knowledge for teaching and the relationship between such knowledge and teacher characteristics. The Learning Mathematics for Teaching project administered a multiple-choice assessment covering topics in number and operation to a nationally representative sample of teachers (n = 625)…