Until recently the testing of a 100-digit number to determine whether it is prime or composite could have taken a century. However, in the past two years a method has been developed enabling a computer to determine the primality of an arbitrary number in about 40 seconds of running time. (Author/JN)

The focus of these worksheets is on whole-number numeration using resource materials such as newspapers, tables of contents, indexes, and almanacs. Notes for the teacher are included. (MNS)

Representation of integers in various bases is explored, with a proof. (MNS)

Problems are discussed in which addition facts are presented using words instead of numbers. The letters are then replaced by numbers that will make the addition problems correct. (MP)

Presents experimental findings that indicate that some number capacity is present in 22-week old infants, long before the onset of verbal counting. Suggests that verbal counting may have precursors present during infancy. (CS)

Four worksheets appropriate for various grade levels 1-8 that can be used to provide experience in classifying numbers according to various attributes are given. (MK)

A procedure for recording the prime factors of a composite number is explained. (DT)

Conjectures about triangular arrangements of nine digits are stated and proved. (DT)

A method is given for determining what months will have a Friday the thirteenth for any given year. (DT)

Examined development of number concepts among participants from the beginning and end of first grade, third and fifth grades, and university. Found that the numerical distance effect appeared in all groups. Found size congruity effect began to appear at the end of first grade. Proposed a model of internal representation of magnitude asserting that…

Presents activities that are the result of reflections on trial-and-error experiences teaching about numbers to young children. (ASK)

Recent work suggests that infants rely on mechanisms of object-based attention and short-term memory to represent small numbers of objects. Such work shows that infants discriminate arrays containing 1, 2, or 3 objects, but fail with arrays greater than 3 [Feigenson, L., & Carey, S. (2003). Tracking individuals via object-files: Evidence from…

Born in 1707, Leonhard Euler was the son of a Protestant minister from the vicinity of Basel, Switzerland. With the aim of pursuing a career in theology, Euler entered the University of Basel at the age of thirteen, where he was tutored in mathematics by Johann Bernoulli (of the famous Bernoulli family of mathematicians). He developed an interest…

Developmental research suggests that some of the mechanisms that underlie numerical cognition are present and functional in human infancy. To investigate these mechanisms and their developmental course, psychologists have turned to behavioral and electrophysiological methods using briefly presented displays. These methods, however, depend on the…