Is 1900 a leap year?

No, 1900 is not a leap year. A leap year is a year that has an extra day, February 29th, added to the calendar. This adjustment is made to keep the calendar year synchronized with the solar year, which is approximately 365.2422 days long. While most leap years follow a pattern, there are exceptions, and the year 1900 is one such exception.

The rule to determine if a year is a leap year is as follows:

If the year is divisible by 4, it's a leap year.

However, if the year is divisible by 100, it's not a leap year, unless...

The year is also divisible by 400, in which case it is a leap year.

Now, let's apply this rule to the year 1900:

Is 1900 divisible by 4? Yes, it is (1900 ÷ 4 = 475).

Is 1900 divisible by 100? Yes, it is (1900 ÷ 100 = 19).

Is 1900 divisible by 400? No, it's not (1900 ÷ 400 = 4.75).

Since the year 1900 meets the criteria of being divisible by 4 and 100, but not by 400, it does not qualify as a leap year. Instead, it has the standard number of days for a non-leap year, which is 365.

The reason for this exception is to refine the approximation of a solar year. While most years divisible by 100 are not leap years, having them as leap years would introduce too many additional days, causing the calendar to drift out of sync with the solar year. As a result, the calendar system adjusts to strike a balance between precision and simplicity.

In summary, 1900 is not a leap year because although it's divisible by 4 and 100, it's not divisible by 400, and therefore does not meet the necessary criteria to have an extra day added to the calendar.