
First, find the prime factors of 15, 18, and 20. 15 = 3 x 5 18 = 2 x 3 x 3 20 = 2 x 2 x 5 Collect the largest number of occurrences of each prime number. The largest number of times the factor 3 occurs is two. The largest number of times the factor 2 occurs is two. The largest number of times the factor 5 occurs is one. Therefore the L.C.M. is = 3 x 3 x 2 x 2 x 5 = 180. Directions: Find the L.C.M. using the prime factorization method Also write at least 10 examples of your own. 