Presents an algorithm to estimate pi by approximating a unit circle with a sequence of inscribed regular polygons. Demonstrates the application of the algorithm with a hand-held calculator and an Apple computer. Provides a program to calculate pi in Pascal programing language. (12 references) (MDH)

Traditional methods of teaching addition include algorithms that involve right-to-left procedures. This article describes efficient procedures for left-to-right addition and subtraction involving computation and computational estimation that reflect children's natural behaviors observed during activities with unifix cubes. (MDH)