**Algebra**

Algebra at the Airport (November 2008)

Heron Triangles and Moduli Spaces (May 2008)

Filling in the Gaps (April 2008)

A New Path to the Quadratic Formula (February 2008)

Converging on the Centroid (December 2007)

The Jug Problem Reloaded (October 2007)

More on Powers of m, Phone Trees, Symbolic Algebra, and Combinations (September 2007)

Sequences and Polynomials (February 2007)

Painting the Pyramid (November 2006)

The Ubiquitous Catalan Numbers (October 2006)

A Generalization of Two Ancient Formulas (September 2006)

Divisibility Tests (August 2006)

Phone Trees (April 2006)

Relations among Powers of 2, Combinations, and Symbolic Algebra (April 2006)

How Does One Know if a Number Is Divisible by 17? (March 2006)

Revisiting Fibonacci and Related Sequences (January 2006)

Simple Recurrence Relations, Proper Guessing, and Closed-Form Solutions (November 2005)

Things Fall Apart: A Recurrence of Tiling (September 2005)

Fibonacci and Lucas Numbers (May 2005)

Multiplying Everything Using the Difference of Two Squares (April 2005)

Fibonacci Identities, Matrices, and Graphs (February 2005)

Kaprekar's Constant (November 2004)

In-Depth Mathematical Analysis of Ordinary High School Problems (April 2004)

Fibonacci and Related Sequences (February 2004)

Regression Lines through Conic Sections (December 2003)

Integral Factorization of Quadratic Trinomials (October 2003)

Gauss, Pythagoras, and Heron (May 2003)

Match Making: Fitting Polynomials to Tables (March 2003)

**Geometry**

Heron Triangles and Moduli Spaces (May 2008)

Converging on the Centroid (December 2007)

*N*-Mids* *(March 2007)

How Is Geometry in Tune with Bach? (August 2007)

Painting the Pyramid (November 2006)

The Angles between the Sides of a Quadrilateral and Its Diagonals (May 2006)

Trisecting the Circle: A Case for Euclidean Geometry (February 2006)

A Tale of Two Theorems (January 2005)

Circumscribable Quadrilaterals: A Journey in Honors Geometry (October 2004)

A Specific Construction of a Conic from an Ellipse (September 2004)

Regression Lines through Conic Sections (December 2003)

Gauss, Pythagoras, and Heron (May 2003)

**Trigonometry**

Heron Triangles and Moduli Spaces (May 2008)

Choosing (-8)^{1/3} (May 2007)

The Angles between the Sides of a Quadrilateral and Its Diagonals (May 2006)

Fibonacci and Lucas Numbers (May 2005)

A Tale of Two Theorems (January 2005)

**Precalculus**

How to Skew a Parametric Curve (October 2008)

Choosing (-8)^{1/3} (May 2007)

Asymptotic Tangency in Rational Functions (April 2007)

The Where, Why, and How of Solving a^{x }= log_{a}x (May 2006)

Using Similarity to Derive a Formula for the Distance from a Point to a Line (August 2005)

The Chebyshev Polynomials: Patterns and Derivation (August 2004)

**Calculus**

How to Skew a Parametric Curve (October 2008)

An Arc Length Investigation (January 2007)

Calculus Technique of Integration by Parts (August 2005)

Patterns and Sequences

Filling in the Gaps (April 2008)

Unlocking the Simplex Lock (March 2008)

Sequences and Polynomials (February 2007)

The Ubiquitous Catalan Numbers (October 2006)

A Generalization of Two Ancient Formulas (September 2006)

Things Fall Apart: A Recurrence of Tiling (September 2005)

Multiplying Everything Using the Difference of Two Squares (April 2005)

Kaprekar's Constant (November 2004)

The Chebyshev Polynomials: Patterns and Derivation (August 2004)

Fibonacci and Related Sequences (February 2004)

Match Making: Fitting Polynomials to Tables (March 2003)

**Probability**

The Name Game: Exploring Random Permutations (October 2005)

**Technology**

A Specific Construction of a Conic from an Ellipse (September 2004)

Regression Lines through Conic Sections (December 2003)

**Problem Solving and Reasoning**

A Curious Sum with Interesting Dividends (August 2008)

A New Path to the Quadratic Formula (February 2008)

Whole Number Multiplication: There's More to It Than Might Be Expected! (November 2007)

In-Depth Mathematical Analysis of Ordinary High School Problems (April 2004)

**Number and Operations**

Series Subjects (September 2008)

Whole Number Multiplication: There's More to It Than Might Be Expected! (November 2007)

Multiplying Everything Using the Difference of Two Squares (April 2005)

Reducing the Sum of Two Fractions (March 2005)