Introduces RSA, one of the most popular public-key cryptosystems that is used to protect the privacy of computer users. Describes the mathematical foundation of public key cryptography. (KHR)

Describes the development of American apportionments and investigates the mathematics used to determine apportionment. Provides a worksheet for further exploration. (KHR)

Describes an activity in which students use data analysis and mathematical modeling to obtain insight into a geometrical question. Explores a simple case of the isoperimetric inequalities. (KHR)

Describes an activity in which students observe a simple situation, explore conjectures, and generate conclusions from their exploration of the conjectures to develop the essential triangle-congruence theorems. Includes teacher's guide. (KHR)

Discusses how the National Science Foundation (NSF)-funded curricula stack up against the National Council of Teachers of Mathematics (NCTM)'s "Principles and Standards". Identifies distinctive features of the five textbook series and includes an example that shows some of these features for each series. (KHR)

Offers some tips to help make learning logs an integral part of mathematics instruction. Includes examples of learning logs. (KHR)

Describes a credit-card-debt activity that allows students to increase their awareness of underlying mathematical concepts relevant to the world of commerce and personal finance through learning geometric and arithmetic sequences. (KHR)

Presents problems designed to focus student attention on the visual representations that accompany the verbal statements of problem situations involving motion over a period of time. Shows that as a result of engaging in these activities, students gain a better understanding of a given problem situation before they apply procedures to answer…

Presents a method for determining the coordinates of the endpoint of a line segment given its slope, point of origin, and length. Applies the notion of similar triangles to quickly solve this type of problem. Includes a calculator program. (KHR)

Discusses multiple symbols for zero and the long-count system which were used by the Maya. (KHR)

Presents three fundamental ideas of calculus and explains using the coordinate plane geometrically. Uses Cabri Geometry II to show how computer geometry systems can facilitate student understanding of general conic objects and its dynamic algebraic equations. (KHR)

Introduces Hogben's adaptation of Zeno's paradox, "Achilles and the Tortoise", as a thinking and writing exercise. Emphasizes engaging students' imagination with creative, thought-provoking problems and involving students in evaluating their word problem-solving strategies. Describes the paradox, logical solutions, and students' mathematical…

Describes a classroom inquiry into expressing the number pi as the limit of a sequence of different ratios using relationships among coins and the radius of an inscribed circle. (KHR)

Describes an activity designed to demonstrate the birthday paradox and introduce students to real-world applications of Monte Carlo-type simulation techniques. Includes a sample TI-83 program and graphical analysis of the birthday problem function. (KHR)

Sensitizes high school and college teachers to challenges that students often have with mathematical symbols and suggests instructional strategies that can reduce such difficulties. Discusses various uses of symbols and identifies common difficulties encountered as students verbalize, read, and write symbols. Offers teaching strategies that can…