This news article from USA Today talks about the twins born in two different decades. One was born on Dec 31, 2019 and the other on Jan 1, 2020.

First off, congratulations to the parents. I never had twins but I suspect they are awesome fun to raise (a little more work though, I presume). (Knowing me, I would have a large excel spreadsheet of similarities and dissimilarities as they grew up).

Now to my real point. The “spreadsheet numbers guy” in me is having difficulty with the thought that the kids were born in two different decades. Two different years, yes. But two different decades? Not so fast.

The Gregorian calendar starts from Jan 1, 1 AD. (Anything before that was BC. And the previous year was 1 BC. There was no year 0). That would mean, the first decade would have lasted from Jan 1, 1 AD to Dec 31, 10 AD. The second decade would have started on Jan 1, 11 AD. And ended on Dec 31, 20 AD.

If you keep going forward, you will realize that this current decade started on Jan 1, 2011 and will end on Dec 31, 2020. Therefore, we really have not moved on to another decade. That will happen this year end.

(Of course, the non-numbers part of me wants to disregard logic and call everything that is XXX0 to XXX9 to be a decade and just sheepishly admit that our first decade was a year short)

What do you think?

#firstWorldProblems

https://www.usatoday.com/story/news/nation/2020/01/04/indiana-twins-born-different-days-years-decades/2814390001/