"104 Number Theory Problems: From the Training of the USA IMO Team" by Titu Andreescu, Dorin Andrica, and Zuming Feng is a critical resource designed to bridge high school math with rigorous global competitions. The text features 52 introductory and 52 advanced problems, focusing on practical contest strategies and providing detailed, step-by-step solutions for training students in number theory. For more details, visit Mathematical Association of America .