Identities of Shortened Multiplication

The twenty-eighth book in the series "School Mathematical Circles" is devoted to exercises and problems on the application of identities of shortened multiplication, which can be used in extracurricular activities as well as in mathematics lessons for grades 7 to 10.
The book contains the development of 13 mathematical circle lessons with detailed examples, problems for independent solutions, and methodological guidelines for the teacher. A significant portion of the book is occupied by a list of additional problems, their solutions, and comments.
The book is intended for school mathematics teachers and leaders of mathematical circles.