What is the least common multiple (LCM) of 4 and 5?

The least common multiple (LCM) of two numbers is the smallest multiple that is evenly divisible by both numbers. To find the LCM of 4 and 5, we start by identifying the multiples of each number.

The multiples of 4 are: 4, 8, 12, 16, 20, 24, ...

The multiples of 5 are: 5, 10, 15, 20, 25, ...

Next, we look for the smallest number that appears in both lists of multiples. The number 20 is present in both the multiples of 4 and the multiples of 5, making it the smallest number that satisfies the condition of being a multiple of both.

Thus, the least common multiple of 4 and 5 is 20, as there are no smaller common multiples in both sets.