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 2007-01-31, 18:33 #1 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 13×349 Posts Four Fours I don't know if this a new one for some of you OR as old as Mersenne himself The Four 4's Puzzle: For you Disney fans this puzzle is also known as: "The 101 Damn Calculations". Using four 4's and standard mathematical operations formulate equations with the answer being each of the numbers from 0 to 100. All 101 (a prime number!!!) are possible. Every calculation MUST use exactly four 4's and no other digits. The allowable operations are: · Addition: 4 + 4 = 8 · Subtraction: 4 – 4 = 0 · Multiplication: 4 * 4 = 16 · Division: 4 / 4 = 1 · Parenthesis: (4 + 4) / 4 = 2 · Factorial: 4! = 24 · Exponential: 4^4 = 256 · Square-root: √4 = 2 · Concatenation: 44 · Decimal Point: .4 · Repeating Decimal .4 (uses one 4) repeating is equal to 4/9 Examples: 4+4-4-4 = 0 4!*4*(4/4)= 100
2007-01-31, 19:07   #2
DJones

Oct 2006

73 Posts

Quote:
 Originally Posted by petrw1 Examples: 4+4-4-4 = 0 4!*4*(4/4)= 100
Doesn't 4!*4*(4/4) actually equal 96?
(4! + 4/4) * 4 = 100

2007-01-31, 19:16   #3
petrw1
1976 Toyota Corona years forever!

"Wayne"
Nov 2006

13·349 Posts

Quote:
 Originally Posted by DJones Doesn't 4!*4*(4/4) actually equal 96? (4! + 4/4) * 4 = 100
So embarassed...

That should have said 4! * 4 + SQR(4) + SQR(4) = 100

 2007-02-01, 00:54 #4 Wacky     Jun 2003 The Texas Hill Country 21018 Posts We already did this one Please see thread 4756
2007-02-01, 05:30   #5
petrw1
1976 Toyota Corona years forever!

"Wayne"
Nov 2006

11B916 Posts

Quote:
 Originally Posted by Wacky Please see thread 4756
I did check the puzzles forum before I sent this in but didn't find it...

Anyway, sorry for having to ask but how do I go to a specific thread?

Thanks

 2007-02-01, 05:58 #6 Uncwilly 6809 > 6502     """"""""""""""""""" Aug 2003 101×103 Posts 5×7×263 Posts Here is that thread easy style: http://www.mersenneforum.org/showthread.php?t=4756 Notice the form of the url, the t= is the thread number. If it were p= , that would be a post number.
2007-02-01, 17:57   #7
mfgoode
Bronze Medalist

Jan 2004
Mumbai,India

22×33×19 Posts
T and P

Quote:
 Originally Posted by Uncwilly Here is that thread easy style: http://www.mersenneforum.org/showthread.php?t=4756 Notice the form of the url, the t= is the thread number. If it were p= , that would be a post number.

Thank you Unwilly for the info as I often wondered about this too.
But where do you get t=4756 from? Is it from the archives?
Mally

 2007-02-01, 19:34 #8 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 13·349 Posts OKAY...I concede. I was reminded that this puzzle ran a couple years ago....albeit with slightly different parameters....so watch for a companion posting of the Four Nines puzzle....
2007-02-03, 10:42   #9
Andi47

Oct 2004
Austria

2·17·73 Posts

Quote:
 Originally Posted by Wacky Please see thread 4756
This was not the same. In thread 4756, it was allowed to use less than four fours, the "square" operator was allowed (but no SQRT, no exponent)

Here you have to use EXACTLY four fours and a different set of allowed operators. It would be fun to see how far we could complete the list according to the rules in this thread. (a number of things used in thread 4756 would not work here)

Note: squaring seems to be still allowed using x^2 = x^(√4)

let's start with a somewhat "unusual" 1:

1=(4!-4)^(4-4)
3=4-4^(4-4)
5=4+4^(4-4)

 2007-02-03, 11:32 #10 Wacky     Jun 2003 The Texas Hill Country 108910 Posts And just to keep it "interesting", no skipping around. :) You have to wait to post "7" until someone posts a solution for 6", etc. Posting "better" solutions for smaller numbers is fine. And, since this is abour 4's, no more than 4 additions before you give others a chance to play. 0 = 4 + 4 - 4 - 4 1 = (4+4)^(4-4) 2 = 4/4 + 4/4 3 = 4-4^(4-4) (from Andi47) 4 = 4*4^(4-4) 5 = 4+4^(4-4) (from Andi47) Last fiddled with by Wacky on 2007-02-03 at 11:36 Reason: More "rules"
 2007-02-03, 13:49 #11 DJones     Oct 2006 73 Posts Well, as the rules are subtly different, I'll join in. 6 = 4 + ((4 + 4) / 4) 7 = 4 + 4 - (4 / 4) 8 = 4 * 4 - 4 - 4 9 = 4 + 4 + (4 / 4) I appreciate that some of the brackets are redundant, but I believe in making things as clear to comprehend as possible. Last fiddled with by DJones on 2007-02-03 at 13:50 Reason: Typing error