"Mathematics" Manual For The 4Th Grade Of General Secondary Education Institutions (In 2 Parts) As Part Of The Textbook (Bogdanovich M. "Algebra", A Study Guide For The 9Th Grade Of General Secondary Education Institutions That Participate In The Innovative Educational Project Of The All-Ukrainian Level On The Topic "Development And Implementation Of Educational And Methodological Support For General Secondary Education Institutions In The Conditions Of The Implementation Of The State Standard Of Basic Secondary Education" In 2025/2026 Academic Year, In 2 Parts. Part 1 (Authors: Ister O. S., Ister D. O.)