Shows that graphs can reveal much about feedback systems that formula conceal, especially as microcomputers can provide complex graphs presented as animations and allow students to interact easily with them. Describes feedback systems, evolution of the system, and phase diagram. (YP)

Describes an activity which uses the computer to produce an environment that encourages an inductive reasoning approach to ratio and proportion through a billiard ball simulation. Provides examples of graphs and bouncing ball data. (RT)

This paper describes a computer simulation of Buffon's needle problem. The problem considers the probability that a needle will cross a line when the needle is thrown in a random way onto the parallel lines a certain distance apart. The paper provides the algorithm and computer program. (YP)