Seven forms of a programmed booklet based on an eleven-level hierarchy for addition of fractions were developed. One hundred forty-two fourth graders were randomly assigned to treatments; achievement, transfer, retention, and time were compared. No treatment was consistently superior, but developing sequences from hierarchies validated by test…

Different kinds of basic knowledge and strategies necessary for comprehension are examined in three radically different domains: (1) the stories, (2) mathematical problems, and (3) electronic circuits. From analyzing the comprehension processes in these different domains, similarities have emerged in the role of planning knowledge and the…