Finding the Least Common Multiple (LCM)
Warm Up Find the GCF. 15, 70 23, 78 36, 45 11, 55, 121 5 1 9 11
Finding the Least Common Multiple (LCM)
A multiple of a number is the product of that number and a whole number other than zero. Multiples shared by numbers are called common multiples. The lowest common multiple of two or more numbers is called the least common multiple (LCM).
Example 1: Find the least common multiple of 6 and 8. Start listing the multiples of each number and find the first multiple they have in common. 6 – 6, 12, 18, 24, … 8 – 8, 16, 24, … The LCM is 24.
Example 2: Find the least common multiple of 12 and 15. 12 - 12, 24, 36, 48, 60, … 15 – 15, 30, 45, 60, … The LCM is 60.
Example 3: Find the least common multiple of 5, 6 and 10. 5 – 5, 10, 15, 20, 25, 30, … 6 – 6, 12, 18, 24, 30, … 10 – 10, 20, 30, … The LCM is 30.
Practice Find the least common multiple. 8, 10 3, 9 10, 15 3, 6, 8 40 9 30 24
Closure What is the LCM of 22, 55, 60? 660