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2016-10-18, 00:12   #1
Uncwilly
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Aug 2003
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Answer in 5 . 4 . 3 . 2 . 1 .....

The following is borrowed from here.
Quote:
 Take the digits 5, 4, 3, 2 and 1, in that order. Using those digits and the four arithmetic signs — plus, minus, times and divided by — you can get 1 with the sequence 5 - 4 + 3 - 2 - 1. You can get 2 with the sequence (5 - 4 + 3 - 2) x 1. The question is ... how many numbers from 1 to 40 can you get using the digits 5, 4, 3, 2, and 1 in that order along with the four arithmetic signs? You can group digits with parentheses, as in the example. There are no tricks to this, though. It's a straightforward puzzle. How many numbers from 1 to 40 can you get — and, specifically, what number or numbers can you not get?
Let's try to keep it with out powers or bases. Also, let's try to get variants for each number
Color any additions that you make.
Code:
 1 = 5 - 4 + 3 - 2 - 1
2 = (5 - 4 + 3 - 2) x 1
3 = (5 + 4) - (3 x 2 x 1)
4 = -5 + 4 + (3 x 2) - 1
5 = -5 + (4 x 3) - 2 x 1

 2016-10-18, 01:13 #2 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 32×7×73 Posts I'll take 6 and pass it on... 6 = (5 - 4) * (3 * 2 * 1)
 2016-10-18, 01:55 #3 rogue     "Mark" Apr 2003 Between here and the 142078 Posts 7 = 5 - 4 + 3 + 2 + 1
 2016-10-18, 02:00 #4 Jayder     Dec 2012 27810 Posts 8 = 5 + 4 - 3 + 2 * 1 Last fiddled with by Jayder on 2016-10-18 at 02:01 Reason: Formatting
 2016-10-18, 02:14 #5 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 100100101011012 Posts 9 = 54 / 3 / 2 * 1 Because 5+4+3+2+1 = 15, each odd number up to 15 is easy: just change one or more pluses into a minus. It is much more interesting to use a minimal number of signs (less than four; then obviously you will have some more than 1-digit numbers) Last fiddled with by Batalov on 2016-10-18 at 04:12
2016-10-18, 02:59   #6
axn

Jun 2003

132816 Posts

Quote:
 Originally Posted by Batalov 9 = 54 / 3 / 2 * 1
Without cheating...

9 = (5 + 4) * (3 - 2 * 1)

 2016-10-18, 03:44 #7 bsquared     "Ben" Feb 2007 D4B16 Posts 10 = (5 + 4) + (3 - (2 * 1))
 2016-10-18, 04:19 #8 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 41·229 Posts 11 = 5 + 4 + 3 - 2 + 1 12 = 5 + 4 + 3 * (2 - 1) 13 = 5 + 4 + 3 + 2 - 1 14 = 5 + 4 + 3 + 2 * 1 15 = 5 + 4 + 3 + 2 + 1 16 = 5 + 4 + 3 * 2 + 1
 2016-10-18, 04:22 #9 VBCurtis     "Curtis" Feb 2005 Riverside, CA 10010011111002 Posts 17 = (5 + 4*3) * (2-1) 18 = 5 + 4*3 + 2 - 1
 2016-10-18, 04:36 #10 firejuggler     Apr 2010 Over the rainbow 43×59 Posts 19=(5*4)-(3/(2+1)) 20=(5*4)+(3-(2+1)) or 20=(5*4*3)/(2+1) 21=(5*4)+(3/(2+1)) Last fiddled with by firejuggler on 2016-10-18 at 05:35
 2016-10-18, 05:03 #11 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 32·7·73 Posts 22 = (5 * 4) + 3 - 2 + 1

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