The author discusses the use of calculators in calculus classes and difficulties caused by roundoff errors. References for advanced follow-up topics are given. (Author/MK)

Diagnostic teaching is described and discussed. Different types of errors are explained and examples of errors and their possible diagnoses are given. (MK)

Several common errors reflecting difficulties in probabilistic reasoning are identified, relating to ambiguity, previous outcomes, sampling, unusual events, and estimating. Knowledge of these mistakes and interpretations may help mathematics teachers understand the thought processes of their students. (MNS)

What two teachers found when they took a close look at the results of a sentence-solving test given in grades four and five is reported. Error patterns appeared less frequently after instruction but recurred on retention tests. How students can be helped is suggested. (MNS)

This report resulted from work with primary grade children and teachers in Kankakee, Illinois. Essays by four resource persons and two observers are included, each expressing insights and feelings in order to share ideas with resource persons for primary mathematics teaching in other schools. A main objective is to represent the ways elementary…