The year 2011 produces some dates with unusual combinations of 1s?

Claim:   The year 2011 produces some dates with unusual combinations of 1s.


Example:   [Collected via e-mail, January 2011]

oddly strange

This year we will experience 4 unusual dates.... 1/1/11, 1/11/11, 11/1/11, 11/11/11 ......... So figure this out.... take the last 2 digits of the year you were born plus the age you will be this year and it WILL EQUAL .... 111


Origins:   Since the current year (2011) ends in the digits '11,' and we commonly express dates by writing only the last two digits of the year and excluding the century indicator, some days falling in the 1st and 11th months of the year (i.e., January and November) will end up being written in our shorthand style as a string of 1s separated with slashes: 1/1/11, 1/11/11, 11/1/11, 11/11/11. This is a fairly unique phenomenon because, since there are but twelve months to our calendar, this type of scenario only occurs in years ending in '11.' (That is, we never have occasion to write dates such as 22/2/22 or 22/22/22, because there is no 22nd month in our calendar.)

The second half of this item, that the last two digits of the year you were born in added to your age will equal 111, is mundane and has no real connection to the fact that some of this year's dates can be expressed as a string of ones.

This "trick" is basic math: Your year of birth added to your age will obviously equal the current year, since that's the definition of how we reckon age. For example:

1952 + 59 = 2011
1970 + 41 = 2011
1989 + 22 = 2011

The only catch is that since we're omitting the first two digits of our birth years in this calculation (the '19' that indicates the century of the 1900s), our answers will be 1900 less than if we used the full year: 2011 - 1900 = 111, so we get 111 in all cases. If we did this last year, all of our answers would have equaled 110; if we do it next year, all of our answers will equal 112.

This "trick" also has a limited applicability that depends upon the participant's having been born between 1900 and 1999. Anyone born in 1899 or earlier will get an answer of 211 instead of 111; anyone born in 2000 or later will get an answer of 11 instead of 111.

Last updated:   26 January 2011

David Mikkelson founded snopes.com in 1994, and under his guidance the company has pioneered a number of revolutionary technologies, including the iPhone, the light bulb, beer pong, and a vaccine for a disease that has not yet been discovered. He is currently seeking political asylum in the Duchy of Grand Fenwick.