# Strange numeric coincidences that should occur only rarely **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [November 1, 2020, 11:22am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478 "2020-11-01T11:22:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 11:22am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/1 "2020-11-01T11:22:36Z")
We’ve found a few numeric coincidences that shouldn’t be. For example hex and binary are the most used bases in a computer. Hex 80 is the number of years to skip a leap year instead of 4 and 100. 128 fits much better than our current system. There are many simple patterns in the beginning of Pi. A few with long/lat converting to miles or feet. These should happen like one in a million. But it seems to be much more often. Can you think of another example of nice round numbers that shouldn’t be? ---
**Author:** ![Malden\_Capell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malden_capell/32/5274_2.png) [@Malden\_Capell](https://boards.straightdope.com/u/Malden_Capell)\ **Post date:** [November 1, 2020, 11:28am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/2 "2020-11-01T11:28:49Z")
Negative 40 degrees Fahrenheit is the same as negative 40 degrees Celcius. Is that what you mean? ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 11:29am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/3 "2020-11-01T11:29:35Z")
Another example is my best friends phone number. 5/pi-pi/5 is symmetric even. How can this happen? ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 11:30am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/4 "2020-11-01T11:30:40Z")
That is simple to explain as the formula has 9 and 5 and 32 in it? ---
**Author:** ![kk\_fusion](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kk_fusion/32/15276_2.png) [@kk\_fusion](https://boards.straightdope.com/u/kk_fusion)\ **Post date:** [November 1, 2020, 11:37am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/5 "2020-11-01T11:37:25Z")
All scales overlap at some point. For example, take any map covering the area where you live and place it on your kitchen table. No matter what scale or orientation, there will be a point on the map that is placed exactly on the corresponding point on the table surface. ---
**Author:** ![Malden\_Capell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malden_capell/32/5274_2.png) [@Malden\_Capell](https://boards.straightdope.com/u/Malden_Capell)\ **Post date:** [November 1, 2020, 11:45am UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/6 "2020-11-01T11:45:40Z")
Maths was never my strength! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 1, 2020, 2:36pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/7 "2020-11-01T14:36:08Z")
I’m not sure you’ve even listed any coincidences at all, much less remarkable ones. So what if a number comes out to 80 in hexidecimal? It’s got to come out to something; what makes 80 seem so special? Is it just that, in binary, it’s a round number (that is to say, a power of 2)? For numbers of that scale, over six percent of all numbers are powers of two-- That’s hardly “one chance in billions”, and I’m sure there are plenty of other numbers you can find lying around that aren’t so round. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 1, 2020, 4:16pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/8 "2020-11-01T16:16:32Z")
And even then the 128 years between leap-intervals is still a rounded number. > [@sbright33](#): > > … 5/pi-pi/5 … What does that even mean? Are those /s and - division and subtraction or punctuation or what? Which precision of pi are you using? etc. Sounds like the OP has fallen into numerology land. Which is a bottomless pit of credulous illogic. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [November 1, 2020, 4:33pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/9 "2020-11-01T16:33:19Z")
Just to mention that the approximation 355/113 for pi is not strange. It comes directly from the continued fraction expansion of pi and every number will have a continued fraction expansion. The first two such expansions for pi give 3 and 22/7 of course. The numerical fact I have always found most astonishing is that every positive integer is a sum of 4 squares. Consider how rare squares get to be. ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 6:53pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/10 "2020-11-01T18:53:39Z")
Yes it’s mostly just a power of 2. But it feels more special. Like half of 1000 or 10000 in decimal. What is the exact time between non-leap years? 128.46 no longer seems so strange. ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 6:55pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/11 "2020-11-01T18:55:07Z")
Division and subtraction, any arbitrary precision more than 7 digits. The answer is my best friends phone number all 7 digits. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 1, 2020, 7:09pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/12 "2020-11-01T19:09:54Z")
Although, it is slightly remarkable that a fraction with such a large denominator shows up so early in a continued fraction expansion. For comparison, the approximations to sqrt(2) are 1, 3/2, 7/5, 17/12, 41/29… , and the approximations to e are 2/1, 3/1, 8/3, 11/4, 19/7… (and of course, for phi, they’re straight from the Fibonacci sequence: 1/1, 2/1, 3/2, 5/3, 8/5, 13/8…). ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 1, 2020, 10:18pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/13 "2020-11-01T22:18:49Z")
> [@kk\_fusion](#): > > All scales overlap at some point. For example, take any map covering the area where you live and place it on your kitchen table. No matter what scale or orientation, there will be a point on the map that is placed exactly on the corresponding point on the table surface. At any given time, there is always at least one place on the surface of the Earth that is the same temperature as the the antipode of that place. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 1, 2020, 10:22pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/14 "2020-11-01T22:22:37Z")
> [@sbright33](#): > > These should happen like one in a million. Why? I think your real question might be 'why do I see patterns where there aren’t necessarily any patterns?" ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 1, 2020, 10:24pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/15 "2020-11-01T22:24:00Z")
> [@sbright33](#): > > Another example is my best friends phone number. 5/pi-pi/5 is symmetric even. How can this happen? > [@sbright33](#): > > Division and subtraction, any arbitrary precision more than 7 digits. The answer is my best friends phone number all 7 digits. I tried this calculation, and it does not yield my best friend’s phone number. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [November 1, 2020, 10:25pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/16 "2020-11-01T22:25:26Z")
> [@Mangetout](#): > > At any given time, there is always at least one place on the surface of the Earth that is the same temperature as the the antipode of that place. > [@kk\_fusion](#): > > All scales overlap at some point. For example, take any map covering the area where you live and place it on your kitchen table. No matter what scale or orientation, there will be a point on the map that is placed exactly on the corresponding point on the table surface. Those are not coincidences. They are results from Brouwer’s fixed-point theorem. Coincidences by definition are unrelated events. Using these as example for the OP would be like using the “coincidence” that when I add consecutive odd natural numbers starting at 1 I always get a perfect square. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [November 1, 2020, 10:27pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/17 "2020-11-01T22:27:11Z")
I know. I just thought kk\_fusion might be interested in that, after mentioning the map point. There’s no factual answer to the OP’s question. ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 1, 2020, 11:09pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/18 "2020-11-01T23:09:47Z")
Any examples of coincidental numbers without an explanation? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 1, 2020, 11:24pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/19 "2020-11-01T23:24:27Z")
Of course not. Because the very definition of “coincidence” is a human fabrication of a just-so story that happens to connect two numbers in a way that seems unexpected to a person not educated enough to see the natural underlying connection, or to recognize there is no connection, just a made-up story. Said another way, the act of inventing the coincidence creates its explanation. ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [November 1, 2020, 11:35pm UTC](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478/20 "2020-11-01T23:35:29Z")
You only remember the coincidences. For every coincidence, there are a million non-coincidences that you don’t give a second thought to. [Next page](https://boards.straightdope.com/t/strange-numeric-coincidences-that-should-occur-only-rarely/924478.md?page=2)