A student noticed an interesting fact about the base two numerals for perfect numbers. Mathematical explanations for some questions are given. (MNS)

This is one of a series of units intended for both preservice and inservice elementary school teachers to satisfy a need for materials on "new mathematics" programs which (1) are readable on a self basis or with minimal instruction, (2) show the pedagogical objectives and uses of such mathematical structural ideas as the field axioms,…

Some theorems concerning factorization of Pythagorean triples are presented. (SD)

The concept of prime factorization is discussed and two rules are developed: one for finding the number of divisors of a number and the other for finding the sum of the divisors. (MP)

A "neat and general" divisibility algorithm for prime numbers is presented. Five illustrative examples are included. (MNS)

A method for determining quickly whether a given number is prime is described. A table presents equations involving prime numbers between 2 and 149, and a proof of the method is provided. (MNS)

The ability of some individuals with mental retardation to identify prime numbers despite their lack of necessary arithmetical skills is discussed. The article suggests that a distinction between prime and nonprime numbers can be made by utilizing the tendency of visual perception to be symmetrically organized. (Author/DB)

The Euclidean algorithm for finding the greatest common divisor is presented. (MNS)