What is the LCM of 30 and 40? Prealgebra Factors and Multiples Least Common Multiple 1 Answer reudhreghs Apr 6, 2016 #120# Explanation: Go up the multiples of #30# and #40# and find the lowest one that is in both lists of multiples, which is #120#. Answer link Related questions What is the least common multiple of 2, 3, and 7? What is the least common multiple of 9, 36 and 45? What is the least common multiple of 5 and 60? What is the least common multiple of 9, 18 , and 21? What is the least common multiple of 8, 10, 12? What is the least common multiple of 15 and 50? What is the least common multiple of 6 and 9? How do you find the least common multiple of a set of numbers? How do you use least common multiple? How can you find the least common multiple using prime factorization? See all questions in Least Common Multiple Impact of this question 4042 views around the world You can reuse this answer Creative Commons License