NCTM President Glenda Lappan discusses her choice of an article to include in a celebration of 100 years of Mathematics Teacher.

How different proofs of a solution to the Surfer Problem provide answers to the question "Why"?  Explains the lesson taught and several different proofs presented.

This article describes a development of conic surfaces that connects different definitions of the conics. A classroom project using Dandelin Spheres is also described.

This issue's photograph is of a rectangular house and target questions focus on mathematical topics that include isometric drawings, area, and proportional reasoning. Students draw floor plans and elevations of the house and use proportional reasoning to estimate measurements from a perspective drawing and calculate the surface area. Mathematical Lens uses photographs as a springboard for mathematical inquiry. The goal of this department is to encourage readers to see patterns and relationships that they can think about and extend in a mathematically playful way. Mathematical Lens is a regular department of Mathematics Teacher . Includes questions for students and answer key.

A project in which students work together to model real-life phenomena of school bus routes and airport design. They also think about the modeling process as they develop rubrics for evaluating their peers' work. Includes sample rubrics, and describes samples of student work.

This article describes an activity involving the investigation of limits through geometry and algebra concepts, including graphing. The activity involves the use of index cards that students can measure to verify their mathematical conclusions.

The art of storytelling as a means of introducing new mathematics topics. Two sample stories are included: one dealing with solving a radical equation, and the other with trigonometry.