"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 1 and 2 are organized into three sections: Counting, Number Sense, and Numeration; Meaning of Addition and Subtraction and Basic Facts; and Building Computational Fluency. Each module begins with the identification of its "Mathematical Focus" and "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 1 and 2, the authors focus in on the key ideas that are essential for success at these levels: (1) Subitizing, or recognizing sets; (2) Making connections among representations of number; (3) Counting on and back; (4) Understanding that ten is both ten ones and one ten; (5) Recognizing patterns in the numeration system; (6) Understanding multiple meanings of addition and subtraction; (7) Composing and decomposing numbers; Using basic fact strategies and recall; and (8) Performing computation strategies for adding and subtracting two-and three-digit numbers.