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Here is a simple matchstick puzzle. Some creative thinking may be needed.

Make the equation below correct by moving only one matchstick. The use of > or < or not equal to is not allowed. You can't remove the matchstick either.

18 = 08

enter image description here

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    $\begingroup$ probably not what you intended, but rot13(lbh pbhyq "zbir" bar bs gur zngpufgvpxf bs gur "1" gb yvtug vg, chg vg ba gur bgure zngpufgvpx va gur "1" naq jura gurl jrer erqhprq gb nfu, lbh'q unir gur pbeerpg rdhngvba rvtug rdhnyf mreb rvtug) $\endgroup$
    – SteveV
    Commented Feb 8, 2022 at 20:45
  • $\begingroup$ LOL @SteveV. Just moving though. No lighting! $\endgroup$
    – DrD
    Commented Feb 8, 2022 at 20:49

10 Answers 10

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Hmmm... a tag? And creative thinking needed? Okay, why don't we...

...remove the match at the top of the first '8' and place it horizontally at the bottom of the '1', then rotate our viewpoint by 180 degrees (i.e. turn everything upside down). Our 'equation' now appears to spell out '80 = AT' - a phonetic representation of the number! (A.T. = ay-tee)

enter image description here

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    $\begingroup$ BOAT? What does--oh, nevermind. $\endgroup$
    – Exal
    Commented Feb 9, 2022 at 16:42
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    $\begingroup$ Very creative solution! I was surprised it was the intended one given that it moves all of the matchsticks. $\endgroup$
    – noedne
    Commented Feb 10, 2022 at 16:42
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    $\begingroup$ @noedne Technically, we still only move one matchstick - the rest of the work is done by moving yourself to view it from a different angle :) $\endgroup$
    – Stiv
    Commented Feb 10, 2022 at 17:33
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It seems to me that

Positive eight is equal to zero-padded eight Plus eight (positive eight, in other words), equals zero eight, in matchsticks

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    $\begingroup$ I did not think of this creative solution, probably because + sign is moved downward. My solution is different. Nice job. $\endgroup$
    – DrD
    Commented Feb 8, 2022 at 20:46
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Using some creative thinking,

we can stand a matchstick on its end to obtain $\dot{18}=00$.
dot over eighteen equals zero zero
The left-hand side can be interpreted as the derivative of a constant function using Newton's notation, which is equal to 0.

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We can make the following equality by moving one match:

18 = 018
enter image description here

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I don't know if this counts since the sticks are a bit short but, |8|=08 .

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Move the matchstick from the bottom of the 0 to the top left of the 1 and then rotate 180 degrees. No mention of anything about the equation being true for all values, so in this case the equation is true if U is equal to L!

enter image description here

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    $\begingroup$ in C/C++ style, 8 (unsigned integer value) is equal to 8 (long integer value). $\endgroup$
    – Hellion
    Commented Feb 11, 2022 at 17:32
  • $\begingroup$ Indeed, in many programming languages (like C#, VB, F#), ‘U’ and ‘L’ suffixes denote unsigned and long integers, which are equal in positive range of the longs. Good find! $\endgroup$
    – Abel
    Commented Feb 13, 2022 at 23:41
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In my point of view

the left 8 can be horizontal and become infinite.

so

it can be 1/inf = 00

enter image description here

enter image description here

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First, let's assign alphabetical numbers value like A = 1, B = 2, etc. Then, rotate the puzzle 180 degrees. Now we have "80 = 81". If we then move the bottom stick in the "0" to the middle, we get "8A = 81". which, following the values, would be "81 = 81" and satisfies all conditions.

enter image description here

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maybe : 16 >= 08 ? in case >= is allowed, which is not (> or < or not equal to) ...

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    $\begingroup$ How do you get that by moving only one matchstick? $\endgroup$
    – bobble
    Commented Feb 9, 2022 at 3:01
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    $\begingroup$ @bobble $ \ge $ $\endgroup$
    – noedne
    Commented Feb 9, 2022 at 3:49
  • $\begingroup$ fwiw : it could have been 10>=08 as well but still not sure if >= is allowed $\endgroup$ Commented Feb 10, 2022 at 2:11
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I removed the bottom matchstick from the 8 on the left side of the equation making the left side say 1A. I placed that matchstick in the middle of 0 on the right side of the equation making the right side say 88. The whole equation: 1A=88. The puzzle never said anything about the equation being true for all values. In my case, the equation is only true if A is equal to 88.

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  • $\begingroup$ Does this answer work? $\endgroup$ Commented Feb 9, 2022 at 3:05
  • $\begingroup$ Could you show an image of ur solution? $\endgroup$
    – Varun W.
    Commented Feb 17, 2022 at 18:03

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