**From New Scientist #2521, 15th October 2005**

If we assume that 5 miles = 8 kilometres what is the smallest integral number of miles that can be converted to its equivalent integral number of kilometres simply by rearranging the order of the digits of the number?

The publishing of this puzzle means that I now have all puzzles on the site from when I started doing programmed solutions to *Enigma* puzzles (with **Enigma 1361** on 8th October 2005) to the most recent *Enigma* puzzle (**Enigma 1780**), which **New Scientist** have announced will be the last *Enigma* puzzle to be published.

There’s also a complete archive of the first 155 puzzles from **Enigma 1** (22nd February 1979) to **Enigma 155** (8th April 1982), and a handful of other *Enigma* puzzles, bring the current number of *Enigma* puzzles on the site to 577. This means there remain around 1,200 *Enigma* puzzles in back issues of **New Scientist** to track down and solve. (I don’t know the exact number, as some issues of the magazine had multiple puzzles, e.g. **Enigma 243A**, **Enigma 243B** & **Enigma243C** at Christmas 1983 and **Enigma 544a** & **Enigma 544b** at Christmas 1989, and sometimes the same puzzle is posted more than once, e.g. **Enigma 9** & **Enigma 83**, or more recently **Enigma 1757** & **Enigma 1770**).

[enigma1362]

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I think it’s safe to assume that we’re interested in positive integers. This Python program runs in 34ms.

Solution:1260 miles = 2016 kilometres.If you take the true conversion factor 1.609344 you find the error in putting 1260 miles equal to 2016 km is nearly 12 km or over 7 miles! Much closer is 59 mi = 95 km (error 49 m). Better still 325 mi = 523 km (error only 37 m or 70 parts per million). Both mean reversing (not jumbling) the order of digits and are much less than 2016 km. I therefore rate this Enigma as “strange”.