The research reported in this book covers a range of grade levels and I found it interesting as an undergraduate math education researcher. I would recommend this book to researchers at any level that are doing cognitive work around conceptions of number, value, and their representations. (MAA Reviews, May 24, 2020) This is a volume for mathematics education researchers and for anyone who studies the cognitive development of children. Summing Up: Recommended. Graduate students, researchers, faculty. (R. M. Fischer, Choice, Vol. 57 (4), December, 2019)