Interviews were used to find the frequency of different types of errors made by 95 sixth-year Papua New Guinea students on a mathematics test. The general trend was the same as for western students, but the Papua New Guinea students made far fewer careless errors. (MNS)

This experiment involved 176 London children aged six and seven. Their levels of attainment on subtraction were quickly and accurately established by two questions. Then teaching programs were used to help them attain prerequisite skills. To symbolize too soon is a danger to be avoided. (MNS)

The evidence suggests that students in grades 5 through 8 have difficulty relating isometric type drawings to the rectangular solids they represent. Errors made by students were analyzed and the effect of instruction in spatial visualization activities assessed. (MNS)

A model of qualities of mathematical activity was developed within a framework of learning goals. A clinical application of the model is described, in which ninth-grade students were given assignment projects. A hierarchy of effective guidance was established, permitting diagnostic evaluation and progressive development of mathematical activity.…

A test of logic using implicational and disjunctive sentences was given to Chinese and English speakers. No differences were found on "if-then" sentences, but differences were found on "or" sentences. (MNS)

The process of transition from a novice's state to that of an expert, in the domain of decimals, is described in terms of explicit, intermediate, and transitional rules which are consistent yet erroneous. Data from students in grades 6-9 are included. (MNS)

The literature on proportional reasoning is reviewed. After methodology is discussed, strategies used to solve proportion problems, variables that influence performance, and training studies are each considered. (MNS)