This unit describes an experience in informal geometry that is based on work with construction paper and milk cartons. The description is mostly of work actually carried out by children in the elementary grades involving such mathematical concepts as congruence, symmetry, the idea of a geometric transformation, and some basic notions of elementary…

An analysis of the rabbit problem reveals some of the fascinating properties of the Fibonacci numbers. (MP)

A geoboard-related extremal problem dealing with both concave and convex polygons is discussed and a proof is given of the solution. (MP)

An algebraic development of the Fibonnaci sequence, appropriate for use in beginning algebra classes, is presented. (SD)

Described are results obtained by students investigating double-diagrams, including discoveries of properties and accompanying proofs. (MP)

A familiar Christmas song described as a second-year algebra problem is presented in "The Twelve Days of Christmas". Five strategies for solving inequalities are discussed in "Solving Algebraic Inequalities". (JT)

This paper discusses ways of discussing limits in the secondary classroom. Particular attention is paid to showing that hypothesized answers are not limits to given sequences. (SD)

Playing with number patterns can lead students to discover some divisibility tests. (JT)

The similarity between two apparently dissimilar problems is explored. Pascal's triangle is involved. (SD)

Similar rectangles are the basis of a set of activities using newspaper. Topics arising include infinite series and Pythagorean theorem. (MP)

Some mathematical patterns are explored by visualizing and counting line segments, squares, cubes, and relationships between them. (JT)

Patterns emerging when two-digit numbers in various bases are operated on by squaring and summing the digits. (SD)