Battista (mathematics education, Ohio State U.) presents a learning progressions-based model for teaching fractions called cognition-based assessment and teaching, which stresses determining students' levels of sophistication in reasoning, assessing and monitoring the development of their understanding of core ideas, and differentiating instruction to meet individual learning needs. Student work samples and assessment tasks are provided, and an introductory chapter explains the components of understanding fractions. There is no index. Annotation ©2012 Book News, Inc., Portland, OR (booknews.com)