The conversation between human and AI assistant.
Why does February have 28 days? Why 29 in leap years?
Are there any other patterns to how leap years work?
Yes, there are some rules for leap years. A year that is divisible by 4 is a leap year, but if it is also divisible by 100, it is not a leap year unless it is also divisible by 400. For example, the year 1900 was not a leap year, but the year 2000 was because it was divisible by both 4 and 400.