Through investigations, games, and several lessons based on childrens' books, students explore the base ten system through the ten thousands, moving from using concrete manipulatives to working with more abstract numeric representations. Using addition, subtraction, multiplication, and division, students apply their knowledge of place value to solve a variety of problems....

The investigations in this book help second graders build their understanding of the tens and ones structure of our number system. Lessons engage children in comparing and explaining the relative size of numbers, counting larger numbers in two or more ways, and recognizing that the number of objects always remains the same despite different ways of grouping....