Chapter 3 - Adding and Subtracting Fractions - 3.2 Least Common Multiples - 3.2 Exercises - Page 211: 20

72

The LCM of a group of numbers is the smallest number into which the original numbers divide. Therefore, we can list the multiples of each number, and the number that first appears as a multiple of all of the numbers will be the LCM. 8- 8, 16, 24, 32, 40, 48, 56, 64, 72 9- 9, 18, 27, 36, 45, 54, 63, 72 12- 12, 24, 36, 48, 60, 72 18- 18, 36, 54, 72 Therefore, 72 is the LCM of 8,9, 12, and 18.