Question

why year 2100 2200 2300 2500...... will not be leap years

Answer 1

The year which have 366 days they are called leap year and they are divisible by 4.
But 2100 2200 2300 2500 are leap year as they are divisible by 4

Answer 2

Explanation:

Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. ... The years 1600, 2000 and 2400 are leap years, while 1700, 1800, 1900, 2100, 2200 and 2300 are not leap years.