A hierarchy for learning to solve different types of addition with fractions problems was hypothesized on the basis of both content analysis and psychological considerations. Problem types were defined according to the relationship of the two denominators to each other (e.g., equal, prime, etc.) Students in grades 4 through 8 were each given 45…

The purpose of this study was to evaluate a practical procedure for determining the optimum sequencing of pictorial classification tasks in science using mean difficulty indices generated by a standard sample of grade two students. Acquisition of such skills can affect the learner's performance on subsequent material and the teacher's efforts in…