Understanding Elementary Mathematics, a series of hands-on Workbook Modules, was written especially for prospective elementary school teachers in a way that they would actively learn the structures, concepts and foundations of elementary mathematics.
Thumbnail: The abacus is a calculating tool that has been in use since ancient times and is still in use today. The abacus consists of a number of rows of movable beads or other objects, which represent digits. One of two numbers is set up, and the beads are manipulated to implement an operation involving a second number (e.g., addition), or rarely a square or cubic root. (Unsplash Lisense; Crissy Jarvis via Unspash)