Question: is 15 a multiple of 80?
Answer: The multiples of 80 are … , 160, 240, 320, …. The multiples of 15 are …, 225, 240, 255, … ... In the intersection multiples of 80 ∩ multiples of 15 the least positive element is 240. Therefore, the least common multiple of 80 and 15 is 240.