# Temperature Reverse Digits: Extended Puzzler **URL:** \ **Category:** The Show\ **Created:** [October 18, 2016, 3:23am UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141 "2016-10-18T03:23:10Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [October 18, 2016, 3:23am UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/1 "2016-10-18T03:23:10Z")
The question was about a temperature sign where a driver noticed the digits were exactly reversed, comparing deg C vs deg F. 28/82 & 16/61 (C/F) were the two answers. But those numbers are actually rounded to the nearest integer. 28 C = 82.4, and 16 C = 60.8. Here’s an extended version of this puzzler: Are there any combinations in integer pairs that are exact matches? So only pairs that are exact integers are allowed,. 0 and 32 are an exact integer pair, as well as 100 and 212. There’s many others. From that list, are there any where the pair match up when reversed? I don’t think there are any solutions for positive 2 digit integers. Do you agree? If so, what about negative 2 digit integers? I don’t think there are any of those that work either. So what about 3 digit integer pairs? Any exact integer solutions this puzzler? If so , what’s the one w/the fewest digits.? Or is there even one at all? I don’t know, just asking. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 12, 2016, 8:55pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/2 "2016-11-12T20:55:04Z")
I started running an excel table to two decimal places with the formulas. But looking for the reverse matches made me crazy, so I gave up. My eyes got all buzzy and my brain almost exploded. 😨 ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 13, 2016, 11:34pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/3 "2016-11-13T23:34:15Z")
I think there’s a way using Diophantine equations to find them, but the problem is I don’t know how to use Diophantine equations … lol … maybe I’ll check a book out of the library and take a crack at it , thanks for giving it a go yourself TMB! ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 14, 2016, 3:51pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/4 "2016-11-14T15:51:17Z")
I’m absolutely certain there’s a recognition program that’ll do this. Unfortunately, I don’t have it! ---
**Author:** ![BillRussell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/billrussell/32/3179_2.png) [@BillRussell](https://community.cartalk.com/u/BillRussell)\ **Post date:** [November 14, 2016, 6:05pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/5 "2016-11-14T18:05:37Z")
I used excel to check the first 10000 numbers with no matches (0 to 9999ºF) edit, I can email the spreadsheet to anyone interested, or post it online. edit2. also checked negative, to -9999ºF, no matches ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 15, 2016, 1:05am UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/6 "2016-11-15T01:05:40Z")
Bill, were you looking for reverse matches? Direct matches could easily be done by adding a third column subtracting the first column from the second column. All the zeros are matches. Finding reverse matches is a bit more difficult. I’m stumped for a formula. Anybody? ---
**Author:** ![BillRussell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/billrussell/32/3179_2.png) [@BillRussell](https://community.cartalk.com/u/BillRussell)\ **Post date:** [November 15, 2016, 1:35pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/7 "2016-11-15T13:35:47Z")
I loked for reverse matches. I used excel commands LEFT, RIGHT and MID to break the F number down to individual digits, then recombined them in reverse order via the CONCANTENATE command. Then compared the reversed F value to the C value via the IF command. Only needed to check every 9 F values for obvious reasons. you can download the spreadsheet at [wfrjr.com/data/digits2.xls](http://wfrjr.com/data/digits2.xls) EDIT: found an error, had to use the VALUE command to convert the reversed number, which is in text format, to an actual number. Still no matches. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 16, 2016, 12:20am UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/8 "2016-11-16T00:20:29Z")
A tip of the hat to your ingenuity, Bill 😀! ---
**Author:** ![BillRussell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/billrussell/32/3179_2.png) [@BillRussell](https://community.cartalk.com/u/BillRussell)\ **Post date:** [November 16, 2016, 8:29pm UTC](https://community.cartalk.com/t/temperature-reverse-digits-extended-puzzler/96141/9 "2016-11-16T20:29:50Z")
thanks 10 characters