Explore divisibility concepts in natural numbers through this 27-minute mathematics lecture. Learn about the mod operation, review Euclid's division algorithm, and practice long division techniques. Examine the connection between division and multiplication, important divisibility facts, and methods for determining divisibility. Delve into repeated subtraction, division processes, and work through a large divisibility example. Investigate modular arguments with big numbers and tackle the question of whether 13 divides a given number. Gain valuable insights into fundamental mathematical operations and their applications in number theory.