Topic by nesrocks

Posted: 8/23/2005 1:50 PM

Post subject: The Four Fours challenge (math)

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nesrocks

He/Him

Player (246)

Joined: 5/1/2004
Posts: 4096
Location: Rio, Brazil

The challenge is to write sentences which result in integer numbers from 0 to 100 using only four "4". Any math symbol is accepted, even those which have implicit "2" like square root, as long as you don't write any other algarism, you can use any symbol. Example: 0 = 44 - 44 1 = 4/4 + 4 - 4 2 = 4 + 4 - 4 - √4 (square root) 3 = ... and so on You must use ALL four fours on every sentence. Sentences with more or less than four fours aren't valid. You can't use letters like "lim" or "log" Usefull hints: you can write "44" (uses 2 of the four fours) and "444" etc. use ! example: 4! = 4 x 3 x 2 x 1 = 24 use ? (limiar factor) example: 4? = 4 + 3 + 2 + 1 = 10 use exponential represented by ^ example: 4^4 = 256 use square root at will represent by "√" example: √4 = 2 of course, use (), [] and {} at will i won't give any other hints ;) btw, the problem is 100% solvable! all 101 numbers can be written that way. hf PS.: don't go looking on the internets for answers!

aka Nesrocks http://www.youtube.com/user/UoBtExFODA https://nesrocks.com https://twitter.com/bitinkstudios

Posted: 8/23/2005 2:16 PM
(Edited: 8/23/2005 2:31 PM)

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Xaphan

Former player

Joined: 5/24/2005
Posts: 405
Location: France

I got 3 = ( 4 ? + 4 - √ 4 ) / 4 4 = √ 4 + √ 4 + √ 4 - √ 4 5 = ( 4 x 4 + 4 ) / 4 6 = [ ( 4 ? + √ 4 ) / 4 ] * √ 4 7 = ( 4 ? + √ 4 + √ 4 ) / √ 4 8 = √ 4 + √ 4 + √ 4 + √ 4 9 = 4 ? - [ ( √ 4 + √ 4 ) / 4 ] 10 = 4 ? + √ 4 + √ 4 - 4 11 = 4 ? + [ ( √ 4 + √ 4 ) / 4 ] 12 = [ ( 4 ? + √ 4 ) / 4 ] * 4 13 = 4 ? + [ ( 4 ? + √ 4 ) / 4 ] 14 = 4 ? + 4 + 4 - 4 15 = 4 ? + 4 + 4 / 4 16 = 4 ? + √ 4 + √ 4 + √ 4 17 = 4 ! - [ ( 4 ? + 4 ) / √ 4 ] 18 = 4 ? + 4 + √ 4 + √ 4 19 = ( 4 ? - 4 / 4 ) + 4 ? 20 = 4 x 4 + √ 4 + √ 4 I will stop here for now... Tell me if some are wrong or if i was bypassing the rules (i hop that you can use the √ twice in the same line...)

Not dead yet... still very busy... damn...

Posted: 8/23/2005 2:22 PM
(Edited: 8/23/2005 2:33 PM)

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nesrocks

He/Him

Player (246)

Joined: 5/1/2004
Posts: 4096
Location: Rio, Brazil

always use spacing between symbols please, "-" before the "√" is barelly seable :) i think you meant 17 = 4 ! + [ ( 4 ? + 4 ) / √ 4 ] 80 to go :)

aka Nesrocks http://www.youtube.com/user/UoBtExFODA https://nesrocks.com https://twitter.com/bitinkstudios

Posted: 8/23/2005 2:23 PM

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Walker_Boh

Former player

Joined: 4/16/2004
Posts: 1276
Location: Uppsala, Sweden

What's the ?-mark? I know the ! (4! = 4 x 3 x 2 x 1= 24) but the ?-mark I don't know. Nice though ;)

/Walker Boh

Posted: 8/23/2005 2:33 PM

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Xaphan

Former player

Joined: 5/24/2005
Posts: 405
Location: France

4? is the summing operator, it works like the ! operator though you have to add the number between them instead of multiplying them... I shall try to find the others tonight... that's a nice guess FODA

Not dead yet... still very busy... damn...

Posted: 8/23/2005 2:35 PM

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nesrocks

He/Him

Player (246)

Joined: 5/1/2004
Posts: 4096
Location: Rio, Brazil

another issue is to find out how far can one go beyond 100 without breaking the rules ;)

aka Nesrocks http://www.youtube.com/user/UoBtExFODA https://nesrocks.com https://twitter.com/bitinkstudios

Posted: 8/23/2005 2:39 PM

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NrgSpoon

Joined: 6/14/2004
Posts: 646

Xaphan: 16 = 4 ? + √ 4 + √ 4 + √ 4 Kinda overcomplicated here. 4+4+4+4 not good enough?

I like my "thank you"s in monetary form.

Posted: 8/23/2005 3:24 PM
(Edited: 8/23/2005 3:34 PM)

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Itstoearly

Joined: 8/10/2004
Posts: 173
Location: Bethel, VT

16 also = 4 * 4 * 4 / 4 --------------------------- 21 = (44 - √4) / ( √4) 22 = 4 * 4 + 4 + √4 23 = (44 + √4) / ( √4) 24 = 4 * 4 + 4 + 4 25 = 4? * √4 + [(4?) / ( √4)] 26 = 4! + 4 - 4 + √4 27 = 4! + (4/4) + √4 28 = 4! + 4 - 4 + 4 29 = 4! + (4/4) + 4 30 = 4 * 4 * √4 - √4

Posted: 8/23/2005 3:34 PM

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Xaphan

Former player

Joined: 5/24/2005
Posts: 405
Location: France

And so...? easiness is not my moto ;) I shall go for some more : 21 = 4 ? + 4 ? + 4 / 4 22 = 4 ! - √ 4 + √ 4 - √ 4 23 = 4 ! - √ 4 + 4 / 4 24 = ( 4 ? + 4 - √ 4 ) x √ 4 25 = 4 ! + √ 4 - 4 / 4 26 = 4 ! + √ 4 + √ 4 - √ 4 27 = 4 ! + ( 4 ? + √ 4 ) / 4 28 = 4 ! + 4 + 4 - 4 29 = ( 4 ! + 4 ! + 4 ? ) / √ 4 30 = 4 ! + √ 4 + √ 4 + √ 4 I shall post them ten by ten it shall be easier to read

Not dead yet... still very busy... damn...

Posted: 8/23/2005 3:37 PM

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Itstoearly

Joined: 8/10/2004
Posts: 173
Location: Bethel, VT

31 = 4! + 4? - 4/4 32 = 4 * 4 + 4 * 4

Posted: 8/23/2005 4:12 PM

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Xaphan

Former player

Joined: 5/24/2005
Posts: 405
Location: France

33 = 4 ? + 4 ! - 4 / 4 34 = 4 x 4 x √ 4 + √ 4 35 = 4 ? + 4 ! + 4 / 4 36 = 44 - 4 x √ 4 37 = ????????????????????? 38 = 4 ! + 4 ? + √ 4 + √ 4 39 = 4 x 4 ? - 4 / 4 40 = 4 x 4 ? + 4 - 4 41 = 4 x 4 ? + 4 / 4 42 = 4 x 4 ? + 4 - √ 4 43 = ( 4 ! x 4 - 4 ? ) / √ 4

Not dead yet... still very busy... damn...

Posted: 8/23/2005 5:26 PM

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SXL

Joined: 2/7/2005
Posts: 571

Xaphan wrote:

33 = 4 ? + 4 ! - 4 / 4

Itstoearly wrote:

31 = 4! + 4? - 4/4

first is correct, but 31 is wrong... please redo every line before posting it :)

I never sleep, 'cause sleep is the cousin of death - NAS

Posted: 8/23/2005 7:37 PM
(Edited: 8/23/2005 7:41 PM)

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Randil

Skilled player (1827)

Joined: 4/20/2005
Posts: 2161
Location: Norrköping, Sweden

Well, this seems like a lot of fun... I think I'll try to solve this tomorrow if I get the time... Oh and here's 37: 37 = (4+4)? + (4/4) I don't know how to write the square-root symbol, so I'll write sqrt instead. here's the solution to 31: (sqrt4+sqrt4+sqrt4)? + 4?

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Posted: 8/23/2005 7:37 PM

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samurai_goroh

Editor, Player (54)

Joined: 12/25/2004
Posts: 634
Location: Aguascalientes, Mexico

44 = 44 x (4 / 4) 45 = 44 + (4 / 4) 46 = 44 + (4 / √4) 47 = 48= (4? * 4) + 4 + 4

I'm the best in the Universe! Remember that!

Posted: 8/23/2005 7:47 PM
(Edited: 8/23/2005 7:58 PM)

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Randil

Skilled player (1827)

Joined: 4/20/2005
Posts: 2161
Location: Norrköping, Sweden

47 = 4! + 4! - (4/4) 49 = 4! + 4! + (4/4) 50 = 4! + 4! + (4/sqrt4) 51 = (4+4+sqrt4)? + 4 52 = (4?)? - sqrt4 + (4/4) (this one was a little tricky) 53 = (4?)? - (4+4)/4

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Posted: 8/23/2005 7:55 PM

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Quietust

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Emulator Coder, Former player

Joined: 7/14/2004
Posts: 250

52 = 4! + 4! + √4 + √4

* Quietust, QMT Productions P.S. If you don't get this note, let me know and I'll write you another

Posted: 8/23/2005 7:59 PM
(Edited: 8/23/2005 8:01 PM)

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Randil

Skilled player (1827)

Joined: 4/20/2005
Posts: 2161
Location: Norrköping, Sweden

hehe I guess your answer to 52 is simpler than mine Quietust :) 54 = (4?)? -((sqrt4+sqrt4)/4)

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Posted: 8/23/2005 8:00 PM

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Quietust

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Emulator Coder, Former player

Joined: 7/14/2004
Posts: 250

Also, 51 = (4 + 4 + √4)? - 4, not + 4

* Quietust, QMT Productions P.S. If you don't get this note, let me know and I'll write you another

Posted: 8/23/2005 8:02 PM
(Edited: 8/23/2005 8:12 PM)

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Randil

Skilled player (1827)

Joined: 4/20/2005
Posts: 2161
Location: Norrköping, Sweden

Ah, yes you're right. I hate it when I do stuff like that. 55 = (4?)? + (4-4)/4 56 = (4?)? + (sqrt4+sqrt4)/4 57 = (4?)? + (4+4)/4 58 = (4?)? + (4?+sqrt4)/4 59 = (4+4+sqrt4)? + 4 60 = 4! + 4! + 4? + sqrt4 61 = (4?)? + sqrt4 + sqrt4 + sqrt4 62 = (4?+sqrt4)? - 4*4 63 = (4?)? + 4 + sqrt4 + sqrt4

My own page on this site.

Posted: 8/23/2005 8:12 PM

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