The article aims to investigate and develop an interactive e-book to support first graders in self-study on the topic of geometry. The design of interactive e-books ensures the requyrements from the perspective of Psychology - Education, such as creating interactions suitable for the individual characteristics of each student. The authors have designed the e-books, creating an environment for first graders to interact with geometric objects as well as with virtual classmates and teachers in the process of learning, discovering, practicing, applying, and self- assessment. The knowledge units are designed to correspond to the 2018 National Education Program. The e-books help teachers organize teaching in various ways and improve the quality of students’ geometry learning. The case studies and pedagogical experiments show that students self-study and acquyre new knowledge effectively.