Why arnt there leap days in years ending in double zeros?

Answer 1

There can be. Years divisible by 100, but not by 400 are not leap years. So 1900 was not a leap year and 2100 will not be a leap year. The year 2000 was a leap year, because it was divisible by 400. So some double zero years can be a leap year. The next will be 2400.