The Best Simple Matchstick Problem

Uiqoo · **Posted:** Tue May 01, 2012 8:32 am

Ah... Let me see...
Thirteen minus seventy-one equals to four.
Am I right?

Yes.

Attachment:

Matches.png [ 4.78 KiB | Viewed 2300 times ]

(Edit:) What is the minimum number of matches which have to be moved to correct the equation?
Thanks, Gus!

Coaster1235 · **Joined:** Wed Dec 14, 2011 12:25 pm **Location:** Finland

Here's one solution, spoilered:
(Interpret it as |3-7|=4)

Gus · **Posted:** Tue May 01, 2012 8:54 am

Perhaps the problem would be better stated as What is the minimum number of matches which have to be moved to correct the equation?

Uiqoo · **Posted:** Tue May 01, 2012 8:58 am

Coaster1235 wrote:

Here's one solution, spoilered:
(Interpret it as |3-7|=4)

Nice.

Gus wrote:

Perhaps the problem would be better stated as How many matches have you got to move to correct the equation?

Oh, That's a perfect idea. Surely better.

Jared · **Posted:** Tue May 01, 2012 7:23 pm

My answer: Just one! Put the minus sign over the equals sign to make not-equals. 1371 is not 4!

Callum · **Joined:** Sun Mar 04, 2012 9:52 am

I heard another one similar to this today. Move exactly one digit in this equation to make it correct. 62 - 63 = 1

Callum

Darren Grewe · **Posted:** Tue May 01, 2012 8:34 pm

How can 3-7=4?

Wouldn't that be -4 for the answer. If you want to do it the right way it would be 71-13=4 then take away the 1's. Right?!?!

Benf207 · **Posted:** Tue May 01, 2012 8:44 pm

Darren Grewe wrote:

How can 3-7=4?

Wouldn't that be -4 for the answer. If you want to do it the right way it would be 71-13=4 then take away the 1's. Right?!?!

If you're referring to coaster's solutions its the absolute value of 3-7, which is 4. |3-7| = |-4| = 4 . You also couldn't just remove the ones because it says you have to move the match sticks.

Ben

MrSingingPizza · **Joined:** Fri Mar 30, 2012 10:20 pm

My solution: I took the 1 from 71 and turned the 7 into a 9. The equation now reads:
13-9=4. Only 2 matchsticks moved!

xGATOxMALOx · **Joined:** Fri Mar 09, 2012 3:43 am

My solution: 16-7=9 3 sticks moved

Melysa · **Joined:** Thu Nov 05, 2009 7:30 pm **Location:** New York

Answer:

2 matches
From
13-71=4
to
13-17=4

MrSingingPizza · **Joined:** Fri Mar 30, 2012 10:20 pm

MizMelysaLadi wrote:

Answer:

2 matches
From
13-71=4
to
13-17=4

13-17= -4, not 4!

bobthegiraffemonkey · **Posted:** Thu May 03, 2012 6:01 pm

Yeah, I'm cheating too: 13-71=h, where h=-58. 1 matchstick moved.

RubixFreakGreg · **Posted:** Thu May 03, 2012 6:16 pm

Callum wrote:

I heard another one similar to this today. Move exactly one digit in this equation to make it correct. 62 - 63 = 1

Callum

make the 6 on the top right of the 2 as to have 2 to the power of 6 :
_6
2-63=1

2^6-63=64-63=1

Is there another solution ?

Callum · **Joined:** Sun Mar 04, 2012 9:52 am

RubixFreakGreg wrote:

Callum wrote:

I heard another one similar to this today. Move exactly one digit in this equation to make it correct. 62 - 63 = 1

Callum

make the 6 on the top right of the 2 as to have 2 to the power of 6 :
_6
2-63=1

2^6-63=64-63=1

Is there another solution ?

Correct! As far as I know there is no other solution (can someone prove me wrong?).

Callum

Uiqoo · **Posted:** Fri May 04, 2012 12:11 am

Callum wrote:

RubixFreakGreg wrote:

Callum wrote:

I heard another one similar to this today. Move exactly one digit in this equation to make it correct. 62 - 63 = 1

Callum

make the 6 on the top right of the 2 as to have 2 to the power of 6 :
_6
2-63=1

2^6-63=64-63=1

Is there another solution ?

Correct! As far as I know there is no other solution (can someone prove me wrong?).

Callum

That's may an only solution.
BTW, I just found interesting thing... Pretending like just that is in matches, I can move 1 match to correct the equation: 62-63=1.

DLitwin · **Posted:** Fri May 04, 2012 12:22 am

Uiqoo wrote:

BTW, I just found interesting thing... Pretending like just that is in matches, I can move 1 match to correct the equation: 62-63=1.

Ah, nice. Solution: Move the bottom match of the '=' to the '-' to swap them: 62 = 63 - 1

Dave

RubixFreakGreg · **Posted:** Fri May 04, 2012 3:26 am

Good job Dave ! I had though of something with the signs and all, but this never crossed my mind !

The Best Simple Matchstick Problem

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