## Christmas Eve Numerology

*December 24, 2012 at 6:09 am* *
3 comments *

Yes, today is Christmas Eve, but more importantly, it’s December 24. That bodes well for numerologists. Compliments of today’s date, here’s a number puzzle for you.

- Write today’s date in the form mm/dd/yy.
- Remove the slashes (/) to leave a six-digit number.
- Add the digits of that number.
- Divide the six-digit number from Step 2 by the sum you obtained in Step 3.
- Take the square root of the result.

As your special bonus, insert the result of Step 5 where it says **[number]** in the URL below, then enter that URL into your browser. Enjoy! And happy holidays!

www.mathjokes4mathyfolks.com/**[number]**.html

More math…

The result in Step 4 isn’t all that unusual. In fact, there are 120 dates in 2012 that, when the six-digit date is divided by the sum of those six digits, the result is an integer. (If the six‑digit date starts with a leading zero, just drop it.) But the result in Step 5 happens far less frequently — there are only 5 dates in 2012 for which Step 4 yields a square number. Can you find the other four?

Entry filed under: Uncategorized. Tags: 24, Christmas Eve.

1.lukewalsh | December 26, 2012 at 7:02 pmThanks for the puzzle. I made a Desmos graph to help me find the others. https://www.desmos.com/calculator/hww6vavx2v Now I wonder about 2013 and other numerology that can be tested.

2.venneblock | December 28, 2012 at 12:48 pmWow, that’s cool stuff you did with the Desmos calc, Luke! Thanks for sharing. Eli Luberoff (the genius behind Desmos) and I will be presenting a session at the 2013 NCTM Annual Meeting in Denver. Perhaps we can share what you’ve done with attendees.

FYI, I popped all this stuff into Excel. I treated the year as a variable, so I can change that to investigate all dates for a particular year at one time. (I use a much larger version of this file to investigate all kinds of weird calendar numerology, but I stripped this version down just for the concatenation problem.) You can check it out here:

http://mathjokes4mathyfolks.com/files/MathDays-ConcatDivBySumGivesSquare.xls

3.lukewalsh | December 29, 2012 at 7:43 pmNice work with the Excel. I forget how powerful Excel can be. Here is a link to other Desmos graphs I have created. http://wallwisher.com/wall/desmos