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#3 Re: Puzzles and Games » Mathemagic » 2015-04-05 17:21:08

math9maniac wrote:

Pick any 4-digit number at all (should not have the same digit throughout). Rearrange the digits to form as many 4-digit numbers as possible. From the range of numbers (including the one you first picked), subtract the least from the greatest. If the difference is a 2-digit number add the digits together.

The idea behind this is no matter what your answer will always be 9. Yes try it now.

Okay.

1234

1234 1243 1324 1342 1423 1432
2134 2143 2314 2341 2413 2431
3124 3142 3214 3241 3412 3421
4123 4132 4213 4231 4312 4321

4321
1234
----
3087

Well, it's 4 digits but I'll go add it... 3+0+8+7 = 18 (1 + 8) = 9.

Worth that 10 minute typing. BTW, the name of the topic reminds me of a book I borrow in the library at my school. smile

#4 Dark Discussions at Cafe Infinity » Well, long time no see again? » 2015-04-05 17:15:43

mathaholic
Replies: 1

Yeah, I know that it drags to not see you guys again for a long time, and I still hope you remember me. Well, in our place it's summer already, so I will get more active for two months, or even three.

So, I will get those posts counting it's been a long time stuck in the 2000's.

#7 Re: Dark Discussions at Cafe Infinity » Happy new year! » 2015-01-14 18:10:25

Late post. Can someone close this topic now?

#13 Dark Discussions at Cafe Infinity » Happy new year! » 2014-12-31 16:53:54

mathaholic
Replies: 7

It has been a great 2014. Mathematically, 2015 is divisible by 13. But, we should still hope for a good year! Cheers

And, happy new year. smile

#24 Re: Dark Discussions at Cafe Infinity » Math competition... » 2014-12-07 12:55:13

If you insist... but I forgot the questions. tongue

#25 Re: Science HQ » When would the eight planets line up? » 2014-12-07 12:32:13

I have searched about February 4 1962. This such alignment of six planets will happen every 97 years 270 days 13 hours 59 minutes 13 seconds 499.75 milliseconds. So, the next alignment is November 1 2059 at around afternoon in our time (Philippines). So, Americans are so lucky to enjoy the view of February 4 1962. And, I will be a 55-year old who would be blind already. tongue

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