"The Zeroing in on Number and Operations" series, which aligns with the Common Core State Standards and the NCTM Standards on Focal Points, features easy-to-use tools for teaching key concepts in number and operations and for addressing common misconceptions. Sharing the insights they've gained through decades of mathematics teaching and research, Linda Dacey and Anne Collins help teachers focus on what students really need to know and understand at each grade level. The modules for Grades Pre-K-K are organized into three sections: Numbers, Relationships, and Addition and Subtraction. Each module begins with the identification of its mathematical focus and the potential challenges and misconceptions associated with those ideas. In the Classroom then suggests instructional strategies and specific activities to implement with students. Meeting Individual Needs offers ideas for adjusting the activities to reach a broader range of learners. Most activities are supported by a reproducible (located in the appendix), and References/Further Reading provides resources for enriching teachers' knowledge of the topic and gathering more ideas. At grades Pre-K and K, the authors focus on the key ideas that are essential for success at these levels: (1) counting by rote, that is, saying the sequence of counting numbers in order; (2) counting rationally (with one-to-one correspondence and cardinality); (3) subitizing, or recognizing sets; (4) counting by tens and ones; (5) making connections among representations of number; (6) comparing and ordering sets and numbers; (7) composing and decomposing numbers; (8) modeling addition as the joining of sets; and (9) modeling subtraction as the separating of a set.