The chain rule is one of the hardest ideas to convey to students in Calculus I. It is difficult to motivate, so that most students do not really see where it comes from; it is difficult to express in symbols even after it is developed; and it is awkward to put it into words, so that many students can not remember it and so can not apply it…

The concept of percentile is a fundamental part of every course in basic statistics. Many such courses are now taught to students and require them to have TI-82 or TI-83 calculators. The functions defined in these calculators enable students to easily find the percentiles of a discrete data set. (PVD)

Discusses the rationale behind the technique of rationalizing the denominator in algebra. Argues that the importance of this technique is greatly exaggerated and is usually unnecessary. Examines an appropriate application of rationalizing the denominator. (ASK)