$6 6 6 6 = 58$
$+ - * /$ and $()$ only
58 must remain as 58, (not 5 + 8, etc.)
$+ - * /$ and $()$ only
58 must remain as 58, (not 5 + 8, etc.)
$66 - 6 - 6 = 58$
(at least in the base-14 system).
6*(6+6)+6
in same base and 6*6*6+6
in another nice base. And 6*(6+6+6)
in 20.
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Commented
Oct 1, 2016 at 22:33
Lateral thinking solution #507:
$66-6-6+4=58$
The $4$ is a $/$ over a $+$.
Here's a fun possibility:
Adding just '/': $6666 \ne 58$
My guess is that the desired answer is:
6()-(6+6)/6 = 58 meaning 60 - 12/6 = 58
Maybe
$-(-6-(6*6)-16)=58$ ; where the $1$ is a sideways minus sign
Explanation
$-(-6-36-16) = -(-42-16) = -(-58) = 58$
You can run my code here which takes as input the number of test cases on one line, and then for each test case there are four lines, each the value of one of $a,b,c,d$ which can have any of the operations occur on them as long as the result is an integer. It prints out all of the resulting possibilities. It was marked correct when submitted to this online judge. This is not a full answer, but I believe this means that there is no valid way to do this without lateral-thinking, for which there is no tag.
6
6
6
6
as input shows that this is impossible without lateral-thinking. I would like to upvote this, but at the moment it is not an answer so I cannot.
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Commented
Oct 1, 2016 at 20:30
The closest I can get is
(6**6)/(6!)-6 = 58.8
it needs to be cast to an integer
But yes, factorials and rounding are not allowed.
Probably invalid, but a creative lateral-thinking attempt:
$(66-66)_1=58$
Note that the number is: $(0000000000000000000000000000000000000000000000000000000000)_1$
Using leading zeroes...
I'm going for:
$\dfrac{-6-6-6}{6}=5-8$ and $\dfrac{6+6+6}{6}=-5+8$
How about:
$6+6+(6/6)=5+8$
This works because
$6 + 6 = 12$ and $6 / 6 = 1$, so $12 + 1 = 13 = 5 + 8$.