When You've Got OCD (And Time)

[More than likely, this has been known for a long time, but hey, at least I re-discovered it on my own^]

I've noticed something fun about the nine o'clock hour.  Take any random minute of the hour -- say 9:23.  If you add the digits of the minutes together, numerology-style, the sum is 2+3=5.  Add the sum to the hour 9, and you get 9+5=14.  Add the digits of that sum together, 1+4, and the resulting sum is identical to the sum of the minute digits, 5.  Works for every minute of the nine o'clock hour.  Take 9:43, for another example.  4+3=7.  9+7 yields 16, and again, 1 and 6 add up to 7.

If the sum of the minute digits exceeds 10, add up the digits of that sum again, and that secondary sum will work the same.  For example, with 9:57 you have 5+7=12, exceeding 10, so add the digits up again: 1+2=3.  Then add the hour 9, and voila, you have 9+3=12!

And if you don't add up the digits of the 10+ minute sum (12 in this case), interestingly enough, this happens:  9+12=21, add the digits of that sum together, and you have 2+1=3, which is the same as the sum of the original minute digits:  5+7=12, and 1+2=3!