Most recent change of 1089

Edit made on June 11, 2016 by ColinWright at 19:53:17

Deleted text in red / Inserted text in green
WW WM
HEADERS_END
Here's a neat trick:
[[[>40 For example:
* Start with 672
* Reversing it gives 276
* 672 - 276 is 396
* 396 reversed is 693
* 396 + 693 is ... ?
]]]
* Pick any 3 digit number, where the first and last digits are different.
* Reverse it
* Subtract the smaller from the larger
* Take this answer and reverse it
** (insert a zero in the front first if it is not 3 digits still)
* Now add these two numbers

Compare your answer with the title of this page...
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Enrichment:
* Does it always work? ~work?
* What about with 4 digits?

David Acheson has written a wonderful little book called !/ "1089 and all that." !/
Most highly recommended.