Hence Least Common Multiple is 2 2 2 2 3 3 7 1008. Find the prime factorization of 7 7 7. Factor Game Math Connections Factors And Multiples Teaching Math To get the Least Common Multiple LCM of 18 and 21 we need to factor each value first and then we choose all the factors which appear in any column and multiply them. . 2 1 3 1 7 1 42. LCM 3 7. Prime factorization of 7 14 and 21 is 7 7 1 2 7 2 1 7 1 and 3 7 3 1 7 1 respectively. How to find LCM by Prime Factorization. The LCM of 7 and 21 is the product of all prime numbers on the left ie. Then multiply all the prime factors with last row quotient of common division that is LCM18 88 7 21 2 x 2 x 2 x 3 x 3 x 7 x 11 5544. Multiply each factor the greater number of times it occurs in steps i or ii above to find the LCM. Where 18 is a positive integer 21 is a positive integer 252 is the lcm of 18 21 and 36 2 3 3 in 2 x 3 x 3 3 x 7 2 x 2 x 3 x 3 are the most re...