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Move one stick

Posted: Wed Jul 27, 2016 4:24 pm UTC
by SirGabriel
I've seen this puzzle a lot lately:

Move just one match to fix the equation!
Image


Finding one or two solutions is easy, but how about finding all of them? How many different ways can you move just one match to make a true statement?

Re: Move one stick

Posted: Wed Jul 27, 2016 4:29 pm UTC
by SirGabriel
I've come up with 13 solutions so far.
Spoiler:
8 - 4 = 4
5 + 4 = 9
0 + 4 = 4
5 + 4 ≠ 4
6 - 4 ≠ 4
6 + 4 > 4
5 + 4 ≥ 4
6 - 4 ≤ 4
6 ≠ 4 - 4
6 ≮ 4 - 4
5 ≮ 4 = 4
6 > 4 = 4
5 ≠ 4 = 4

Re: Move one stick

Posted: Wed Jul 27, 2016 6:20 pm UTC
by thunk
Spoiler:
Move the center bar of the middle 4 to make a 9 on the right. You are left with three matches in the middle--6+3=9.

Re: Move one stick

Posted: Fri Jul 29, 2016 4:19 pm UTC
by HonoreDB
Spoiler:
You get at least one more if you allow bitwise operations:
6 | 4 ≠ 4

Re: Move one stick

Posted: Fri Jul 29, 2016 4:24 pm UTC
by SirGabriel
HonoreDB wrote:
Spoiler:
You get at least one more if you allow bitwise operations:
6 | 4 ≠ 4

I don't know what that means.

Re: Move one stick

Posted: Fri Jul 29, 2016 6:24 pm UTC
by HonoreDB
SirGabriel wrote:
HonoreDB wrote:
Spoiler:
You get at least one more if you allow bitwise operations:
6 | 4 ≠ 4

I don't know what that means.


Spoiler:
A Bitwise OR is an operator in programming, usually written as "|" in languages that have it. It essentially means: Write both values in base 2, then replace every 0 in one number with the corresponding digit of the other number. 6 is 110, while 4 is 10, so 6 | 4 is 6 (4 doesn't provide any 1s that aren't already in 6). It's normally used along with other bitwise operators like AND (&) to allow a number to compactly represent a bunch of different yes-or-no questions.