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Matchstick Equation


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60 replies to this topic

#51 Valic4

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Posted 07 April 2008 - 05:06 AM

I think that to either: (1) move any match over the "=" sign to make an inequality; or (2) tilt the top match of the equal sign to make the "<" symbol would solve things nicely.
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#52 ThunderChicken

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Posted 13 April 2008 - 03:26 AM

Since there were three matches for the 'divided by' sign, you could always have moved one from that and put it at a 45 degree angle on the top of the equal sign to make the equation 23/7 is greater than or equal to 7.
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#53 rhapsodize

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Posted 21 April 2008 - 05:49 PM

Matchstick Equation - Back to the Matchstick Puzzles
Move one matchstick to get the correct equation.

Edit: the answer is correct only to 2 decimal digits (since equals sign has to be kept).



Spoiler for Solution


A lot of people have posted to this answer, and they are ALL WRONG! :o

The pi answer doesn't work, unless you limit it to 2 decimal places. And, while I know that that's where the question was heading, it's just not right to limit it.

Any answer involving a not equal sign or inequality sign doesn't work, because it is NOT an equation, no matter what anyone else has posted. Equation is defined as having an equal sign, and that's it.

So, even with over 50 posts already, I think I came up with a solution that is both unique and correct.

Take one of the matches from the fraction bar, and move it to the top (doesn't matter where).

There are now 8 matches on the top and 4 on the bottom. The fraction bar is smaller in length, but that's a non-issue. 8 matches divided by 4 matches equals 2 matches!
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#54 manxy

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Posted 08 May 2008 - 05:04 PM

OMG. I totally hate this site. Every day its something new that doesn't make any sense. Why don't you guys come up with some real brain teasers or copy some from a book or something. This is retarded. It does not equal pi. Thats as good as saying:

XXII
------ = III because we'll just round that one down pretty hard core to make it work
VII

or

XXII
---- = II because were just gonna truncate that .75 so that this works.
VIII

this is dumb; we cant just go ahead and round down or truncate whenever we feel like it just to make a sorry attempt at a brain teaser. Common, just try a little bit. Just a little.

<!-- s:evil: --><!-- s:evil: -->



Totally agree. No wonder kids have trouble understanding Algebra when we treat the equal sign like this!


i have to say, my maths students firstly don't have a problem with algebra even my lower form pupils.
Secondly, using Pi as 3.14 is totally acceptable as many exam boards on the front of NON calculator papers print that if a question require Pi and does NOT state to leave Pi in the answer, to use Pi as 3.14
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#55 SteveP

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Posted 30 May 2008 - 02:55 PM

Matchstick Equation - Back to the Matchstick Puzzles
Move one matchstick to get the correct equation.

Edit: Move the same matchstick diagonally across the equals sign to make it NOT EQUAL.



Spoiler for Solution


Edited by SteveP, 30 May 2008 - 02:57 PM.

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#56 pgreen1911

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Posted 10 June 2008 - 09:52 PM

you could make the equal sign a greater than... 23/7 is greater than 2
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#57 merydogaru

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Posted 11 September 2008 - 10:07 PM

hard one

Edited by merydogaru, 11 September 2008 - 10:10 PM.

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#58 Blatz

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Posted 12 September 2008 - 03:55 AM

I thought equations used equal signs, and inequalities had the others.
dictionary definition of equation

Actually aesculapius, these are all accepted symbols to make up a well formed equation.
< less than
> greater than
>= greater than or equal to
<= less than or equal to
!= not equal to
= equal to
~= approximately equal to

And the reason the XIIII / VII = II is not correct is because you would actually have XIII / VII = II or X/III / VII = II. If you move the other match to be straight then you have moved 2 matches. XIII is another way to write X-III, so one answer would be X-III/VII = II and this is not a valid equation. 7/7 is not 2. The other answer would come out as (10/3)/ 7 = 2 but
is doesn't equal 2 but rather 0.476 (it actually goes on beyond 3 decimal places). I might be a little off on that, i did it real quick and might have missed a rule on that one lol.


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#59 meltinis

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Posted 16 March 2009 - 10:54 PM

Come on guys - this one is possible to solve correct and with no special characters :rolleyes:

The puzzle is:

XXIII
__ __ __ = II
VII

The solution is... Take one from the top of the left side - break it into tree => one for the top of the square root and two for the plus sign (hard to make in the text editor - please see the attached picture):

XXII
__ __ __ = II
__
VI + I

Or written:

22
------------- = 11 => 22/2 = 11
Sq.r(1) +1

Note that the II which previously was 2 now is 11!

Nice solution, eh :rolleyes:

Attached Images

  • Match.JPG

Edited by meltinis, 16 March 2009 - 10:56 PM.

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#60 typodestoyer

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Posted 22 March 2011 - 11:22 PM

I don't like when people say 22/7=pi. However, very creative solution. The non-equals sign is the most correct, however, it works for most math-matchstick puzzles.
P.S. I am a pi freak. I know Pi up to (3.14159265358979323846264338327950288419716975105) however many digits that is by heart.
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