A study to determine if "random" or "careless" errors in multiplication made by individual students take on discernible patterns is described. Implications for teaching are discussed. (MK)

The informal subtraction strategies that children develop are discussed in detail, with the role of the counting-down strategy described. Problems and remedies for difficulties caused by counting backward and the double count are also presented. (MNS)

Examples of four interviews are presented to serve as sample evidence in support of more comprehensive diagnostic procedures in assessing reliably and validly the weaknessess and strengths of learners. The search for computational errors is seen to go beyond standard paper and pencil tests. (Author/MP)

Some research about students with learning disabilities that textbook publishers need to consider as they revise problem-solving materials is briefly cited. (MNS)

Dialogue from an interview with a child about division basic facts is presented. The facts are considered by groups, and specific errors are noted. Finally, remediation ideas are given. (MNS)