Leap Years

A leap year is a year that has 366 days. The month of February, which typically has 28 days, has 29 days during leap years.

NASA.gov:: APOD:2004 February 29 - Julius Caesar and Leap Days

   "In modern terms, the time it takes for the Earth
    to circle the Sun is slightly more than the time
    it takes for the Earth to rotate 365 times (with
    respect to the Sun -- actually we now know this
    takes about 365.24219 rotations)."

365.24219 written as a mixed number is...

        24,219
   365 -------
       100,000

2004 was a leap year.

       February 2004
   Su Mo Tu We Th Fr Sa 
    1  2  3  4  5  6  7
    8  9 10 11 12 13 14
   15 16 17 18 19 20 21
   22 23 24 25 26 27 28
   29

2005 was not a leap year (i.e. it was a common year).

       February 2005
   Su Mo Tu We Th Fr Sa 
          1  2  3  4  5
    6  7  8  9 10 11 12
   13 14 15 16 17 18 19
   20 21 22 23 24 25 26
   27 28

Prior to 1753, a year was a leap year if it was evenly divisible by four. After 1752, a year was/is a leap year if it is evenly divisible by four and not by 100, or it is evenly divisible by 400.

       February 1752
   Su Mo Tu We Th Fr Sa 
                      1
    2  3  4  5  6  7  8
    9 10 11 12 13 14 15
   16 17 18 19 20 21 22
   23 24 25 26 27 28 29
   
   1752 was a leap year because 4 evenly divides into 1752

      September 1752
   Su Mo Tu We Th Fr Sa 
          1  2 14 15 16
   17 18 19 20 21 22 23
   24 25 26 27 28 29 30

In the Gregorian calendar, 303 of every 400 years are common years.

  1. Was year 2000 a leap year?
  2. Was year 1900 a leap year?
  3. Will year 2008 be a leap year?
  4. Will year 2010 be a leap year?
  5. Will year 2038 be a leap year?
  6. Will year 2100 be a leap year?
  7. Will year 10,000 be a leap year?


Creator: Gerald D. Thurman [gthurman@gmail.com]
Created: 24 February 2005

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