The Least Common Multiple (LCM) of two or more numbers is the smallest multiple that is evenly divisible by each of the numbers. For example, the LCM of 4 and 5 is 20, as it is the smallest number that both 4 and 5 can divide without leaving a remainder. Finding the LCM is useful in various mathematical applications, such as adding fractions with different denominators. To calculate the LCM, one can use several methods, including listing multiples, using prime factorization, or applying the relationship between the LCM and the Greatest Common Divisor (GCD). The formula is LCM(a, b) = (a × b) / GCD(a, b). This approach simplifies the process and helps in solving problems involving multiple numbers efficiently.