This yearbook contains articles that give insight into students' thinking about factions, ratios, and proportions. Suggestions are offered on how to develop the concepts and skills associated with these topics. The book is divided into elementary, middle school, and professional development sections. Chapters include: (1) "The Development of Students' Knowledge of Fractions and Ratios" (John P. Smith); (2) "Children's Development of Meaningful Fraction Algorithms: A Kid's Cookies and a Puppy's Pills" (Janet M. Sharp, Joe Barofalo, and Barbara Adams); (3) "Organizing Diversity in Early Fraction Thinking" (Susan B. Empson); (4) "Using Manipulative Models to Build Number Sense for Addition and Fractions" (Kathleen Cramer And Apryl Henry); (5) "Young Children's Growing Understanding of Fraction Ideas" (Elena Steencken and Carolyn A. Maher); (6) "Go Ask Alice about Multiplication of Fractions" (Susan B. Taber); (7) "Examining Dimensions of Fraction Operation Sense" (Deann Huinker); (8) "Part-Whole Comparisons with Unitizing" (Sue Lamon); (9) "Butterflies and Caterpillars: Multiplicative and Proportional Reasoning in the Early Grades" (Patricia Ann Kenney, Mary M. Lindquist, and Cristina L. Heffernan; (10) "Percents and Proportion at the Center: Altering the Teaching Sequence for Rational Number" (Joan Moss); (11) "Making Explicit What Students Know about Representing Fractions" (Barbara M. Moskal and Maria E. Magone); (12) "Using Literature as a Vehicle to Explore Proportional Reasoning" (Denisse R. Thompson, Richard A. Austin, and Charlene E. Beckmann); (13)"Proportional Reasoning: One Problem, Many Solutions!" (Suzanne Levin Weinberg); (14) "Using Representational Contexts to Support Multiplicative Reasoning" (Laura B. Kent, Joyce Arnosky, and Judy McMonagle); (15) "Fraction Division Interpretations" (Rose Sinicrope, Harold W. Mick, and John R. Kolb); (16) "Developing Understanding of Ratio and Measure as a Foundation for Slope" (Joanne Lobato and Eva Thanheiser); (17) "Using Technology to Teach Concepts of Speed" (Janet Bowers, Susan Nickerson, and Garrett Kenehan); (18) "Developing Students' Proportional Reasoning: A Chinese Perspective" (Jinfa Cai and Wei Sun); (19) "The Development of Rational Number Sense" (Irene T. Miura and Jennifer M. Yamagishi); (20) "Multiplicative Reasoning: Developing Student's Shared Meanings" (Cristina Gomez); (21) "Fraction Instruction That Fosters Multiplicative Reasoning" (Lee Vanhille); (22) "Profound Understanding of Division of Fractions" (Alfinio Flores); and (23) "Connecting Informal Thinking and Algorithms: The Case of Division of Fractions" (Daniel Siebert). (KHR)