I think it means that the digits that constitute the bigger digit should be the same for the day, month and last two digits of the year, like the 11th day, 22nd day..etc. 12 is a two digit digit

it's the last set of repeating, single-digit dates that we'll see for almost a century (until January 1, 2101), or a millennium (mark your calendars for January 1, 3001), depending on how you want to count it.

And what does this have to do with the team challenge? Is that when the next one is?

very hard source, good luck teams

nein! nein! nein!

Aaahh...

So 10-10-10 will be the last double-digit date we'll have until just over a year later!

BTW the geek in me must note that 101010 is binary for 42 which is, of course, the answer to life the universe and everything. So mark your calendars because the world may either end, find world peace, or do absolutely nothing out of the ordinary that day!