The conversation between human and AI assistant.
How many numbers between 100 and 500 are divisible by 3 or 7?
Wow, that was quick! How did you figure that out?
I used a method called the inclusion-exclusion principle. It's a technique for counting the number of elements in a set that satisfy certain properties, while taking into account any overlapping elements that satisfy multiple properties. In this case, we first count the number of numbers that are divisible by 3, then count the number that are divisible by 7, and then subtract out the number that are divisible by both 3 and 7, since we don't want to count them twice.