The multiples method is the most common technique of finding the LCM, or least common multiple, of a set of numbers. While there are other methods available, this option is easier to understand and also saves time, especially during an exam.
- Identify the set of numbers that need an LCM
Good examples of numbers that are used to find the least common multiple are the numbers 5, 6 and 15. After identifying your set of numbers, write them down for easier calculation.
- List the multiples of the set of numbers
The multiples of 5 include 10, 15, 20, 25, 30, 35 and 40. The multiples of 6 include 12, 18, 24, 30, 36, 42 and 48. The multiples of 15 are 30, 45, 60, 75 and 90. A multiple of a number is a number that does not provide a remainder when divided by another number. For instance, 20 is a multiple of 10 because it divides it twice without a remainder.
- Calculate the LCM from the provided multiples
After listing the multiples of each number in the set, choose the least number that appears in each set. In this case, 30 is the LCM of 5, 6 and 15. It appears three times in the three sets of numbers.