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-2 votes

Four ones and four zeros

A bit of lateral thinking:
11 votes
Accepted

Four ones and four zeros

Edit: I upgraded the solver to include the pattern .1^-x. It can now solve more numbers. I wrote a computer program to automatically search for solutions. My ...
  • 3,745
5 votes

Four ones and four zeros

Some more: 311 to 409 with gaps. Edit by @Joel Rondeau just leaves 326 unsolved in this range. Update: Contribution by @isaacg completes the range.
  • 11.6k
9 votes

Four ones and four zeros

I tentatively claimed that 265 is the answer, since I thought I did a pretty good go at trying to solve it, and didn't manage it. Commenters have managed to fill all the gaps in this answer, from 263 ...
5 votes

Four ones and four zeros

Thanks everyone for your contributions. 203 = 111!!/.1-(0!+0!+0!)!-0! (isaacg) 204 = 11001100 205 = 111!!/.1-(0!+0!+0!)!+0! (isaacg) 206 = 111!!/.1-0!-0!-0!-0! (isaacg) 207 = 111!!*10-0!-0!-0! 208 = ...
  • 49
10 votes

Four ones and four zeros

Continuing from Dante and Weather Vane: (EDIT: Extended it further, but left some gaps. Either other users will fill them, or I will tomorrow, or one of them is the answer. Outstanding numbers are: ...
10 votes

Four ones and four zeros

Continuing from @Dante . . . Any more?
  • 11.6k
7 votes

Four ones and four zeros

First 25 numbers can be written as 1:10-10+10-01 2:(11-01-00)^(01) 3:10+01+10-10 4:(10^10)*(01^01) 5:0111-0010 6:0111-0001 7:(10^11)-01-00 8:(11^10)-0001 9:0110+0011 10:0101+0101 11:0101+0110 12:(10*...
  • 87
8 votes
Accepted

Ernie and the Chance to Save a Beautiful Relationship

First, we look at how many target numbers are reachable from each of the 134,596 possible starting sets. Each target number is formed from an expression with six terms. There are lots of different ...
  • 16.8k
6 votes
Accepted

Equilibrium of differences

(NB: I've chosen to interpret "the four numbers Alice chooses must be non-repeatable" as "Alice cannot choose the same digit more than once". There are other possible ...
  • 71.5k
0 votes

What's the fewest weights you need to balance any weight from 1 to 40 pounds?

Once we have determined that the weights must be 1, 3, 9 and 27 grams, an obvious question to ask is how to use these weights to weigh an object. One method, which is my candidate for most efficient, ...
0 votes

An Hourglass Puzzle

21 min When one of the hourglasses ends, we can return the same hour or the other hour. If we return the 11-minute hourglass after the 6-minute hourglass has expired twice (only 1 minute has passed) ...

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