Welcome to Episode 6 of Season 1: Unlocking Number Theory and Algebra! This episode dives into various number theory problems, primarily focusing on the application of modular arithmetic and the Chinese Remainder Theorem. Many problems involve finding remainders, solving congruences, or determining properties of integers. The solutions demonstrate techniques for simplifying complex problems into smaller, more manageable modular equations. Several problems utilize Fermat's Little Theorem, and the explanations frequently break down larger problems into smaller, relatively prime components for easier calculation. The source material appears to be preparatory materials for math competitions.