This publication is an abstracted compilation of 15 investigations selected from other journals. The information includes purpose, rationale, research design and procedures, findings, interpretations, abstractor's comments, and references. This journal includes the following reports: (1) "A Constructivist Approach to Numeration in Primary School: Results of a Three Year Intervention with the Same Group of Children"; (2) "Identifying Fractions on Number Lines"; (3) "Teachers' Pedagogical Content Knowledge of Students' Problem Solving in Elementary Arithmetic"; (4) "Representation of Addition and Subtraction Word Problems"; (5) "Effect of Cognitive Entry Behavior, Mastery Level, and Information about Criterion on Third Graders' Mastery of Number Concepts"; (6) "The Effects of Computer-Assisted and Traditional Mastery Methods on Computation Accuracy and Attitudes"; (7) "An Investigation into the Use of Microcomputers to Teach Mathematical Problem-Solving Skills to 13 Year Olds"; (8) "Differences among Women Intending to Major in Quantitative Fields of Study"; (9) "Characteristics of Unskilled and Skilled Mental Calculators"; (10) "Intrinsic Orientation Profiles and Learning Mathematics in CAI Settings"; (11) "Putting the Student into the Word Problem: Microcomputer-Based Strategies that Personalize Math Instruction"; (12) "The Mathematics of Child Street Venders"; (13) "A Cognitive Approach to Meaningful Mathematics Instruction: Testing a Local Theory Using Decimal Numbers"; (14) "Teaching Children to Use Schematic Drawings to Solve Addition and Subtraction Word Problems"; and (15) "Effect of Assignment Projects on Students' Mathematical Activity." The titles and sources of mathematics education research studies reported in CIJE and RIE, April-June 1988, are listed. (YP)