Presents an active way for students to learn about SAS, SSS, ASA, AAS, and HL in determining congruent triangles. (Author/NB)

Demonstrates how to use graphing calculators to explore rational number approximations to irrational numbers. (Author/NB)

Poses a problem in which readers are asked to determine which pentomino pieces will form a square. (YDS)

Presents student solutions to a problem using different strategies that focus on kitchen geometry. (YDS)

Discusses a student's experiences as she completes a homework assignment on measurement. Links literature and mathematics in an appealing and meaningful way. (Author/NB)

Poses the Fractionberry Pie problem to teach students fractions. (Author/NB)

Presents the March Mathness problem which allows students to mathematically analyze familiar situations. Uses sports as the analogy. (Author/NB)

Presents a variety of activities in which 4th grade students investigate prisms and pyramids by building models from folded paper and drinking straws. (Author/NB)

Presents the Shape Search problem to develop student visualization. Focuses attention on the National Council of Teachers of Mathematics (NCTM) Geometry Standard. (Author/NB)

Describes an exploration into the concept of the rate of convergence in a university classroom. It is well known in mathematics that this concept leads to a modern construction of infinitesimals and their orders. (Author)

This classroom study supported and documented the emergence of multiple senses of mathematical similarity. Findings showed a shift toward modeling, which introduced an epistemological dissonance between mathematics and science. Postinstructional interviews suggested that most children came to appreciate the mathematical generalizations afforded by…

Presents an historical lesson on the development of numbers and the special characteristics of zero. Includes activity sheets designed to help students focus their attention on the value of numerals including zero, place value, and operation with zero. (KHR)

Suggests an alternative proof by analytic methods, which is more accessible than rigorous proof based on Euclid's Elements, in which students need only apply standard methods of trigonometry to the data without introducing new points or lines. (KHR)

Presents a lesson to teach matrices that emphasizes conceptual understanding and allows students to extend their investigations into important and relevant situations by using graphing calculators after important conceptual understanding has been developed. (KHR)

Presents Cevian geometry problems (involving a segment that joins a triangle's vertex to a non-vertex point on opposite side) that illustrate how to implement methods for developing flexible strategies of problem solving, finding multiple representations, and making connections to other areas of mathematics and the real world. (ASK)