What is the least common multiple of 3 and 7?

To find the least common multiple (LCM) of two numbers, you need to determine the smallest multiple that is common to both numbers. In this case, we are examining the numbers 3 and 7.

Both 3 and 7 are prime numbers, meaning they have no common factors other than 1. To calculate the LCM of two prime numbers, you can simply multiply them together. The multiples of 3 are 3, 6, 9, 12, 15, 18, 21, and so on. The multiples of 7 are 7, 14, 21, 28, and so on.

The first common multiple that appears in both lists is 21. Thus, the least common multiple of 3 and 7 is 21. This makes 21 the correct answer, as it is the smallest number that can be evenly divided by both 3 and 7.

When determining the LCM, it's important to note that selecting other values like 10, 12, or 24 does not meet the criteria, as they are not multiples of both 3 and 7. Hence, 21 is uniquely positioned as the least common multiple of the two