for fixing damaged, incomplete, or error-prone PDF files (suitable if "15 Fix" means a page 15 error or 15th fix method).
The book is noted for including original work and copyrighted formulas by the author. Key technical areas include: Google Books Fundamental Number Theory : Factors, HCF/LCM, and Number Introduction. Advanced Calculation : Vedic Maths, Base Systems, and Cyclicity. Special Functions
Instead of fixing a broken PDF, buy or borrow a legal copy:
Based on user reports, "Page 15" in some versions of Concepts of Numbers contains complex mathematical notations, diagrams, or tables. Common reasons for failure: