① A leap year is a year in which ordinary years can be divisible by 4 (for example, 2004 is a leap year, 190 1 is not a leap year).

② A leap year is a century year divisible by 400 (for example, 2000 is a leap year, and 1900 is not).

(3) A year with a large number can be divisible by 3200, but it can also be divisible by 172800, which is a leap year (for example, 172800 is a leap year, but 86400 is not).