OK, here we go. The black lines in the diagram below represent matchsticks. Can you make the equation correct by moving only 1 match? Oh, and you can’t place one across the equals sign to make it ‘not equal to’!
As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.
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September 23, 2011 at 7:03 am |
2 seconds. One of the easiest.
September 23, 2011 at 7:04 am |
Hurrah! 10 seconds once you wrap your head around the numbers in a rational way.
September 23, 2011 at 7:06 am |
Think I have it in under a min
September 23, 2011 at 7:10 am |
If it is the answer I am thinking of, it is cute.
September 23, 2011 at 7:15 am |
I’m predicting objections come Monday…
September 23, 2011 at 8:16 am
But then again…
September 23, 2011 at 9:20 pm
me too
September 23, 2011 at 7:16 am |
I’m never sure if you’re supposed be thinking literally or laterally for these puzzles.
September 23, 2011 at 7:16 am |
Easy, but I’m not sure as it’s not really equal.
September 23, 2011 at 7:44 am
I wonder what your answer is then…
September 23, 2011 at 7:17 am |
done in a few minutes but not sure if I’m technically allowed to do what I did
September 23, 2011 at 1:32 pm
Same here. I have a solution but I doubt its as brilliant as the real answer.
September 23, 2011 at 1:38 pm
I determined a second solution. This time I think I have got it!
September 23, 2011 at 7:19 am |
Solved. … Mmm
September 23, 2011 at 7:19 am |
yeah, as some people said above… got what i think is the intended answer for the puzzle, but believe it makes the puzzle ever so slightly incorrect.
September 23, 2011 at 7:24 am |
I can only do it by moving 2 matches
September 23, 2011 at 7:27 am |
I’ve got a correct answer, in a literal way. Although it looks like some of the match sticks are a bit to close to each other to get the one match stick in the right position. But it is a good answer.
September 23, 2011 at 7:41 am
Hey, there is a second solution which is very comparable! And that one does fit.
September 23, 2011 at 7:34 am |
Hahaha, great one! Though the equal-sign might be a wee bit misleading in my solution…
September 24, 2011 at 11:09 am
Equal sign is grey – so I dont think we allowed to mess with it. I suppose you could ADD to it.
September 23, 2011 at 7:38 am |
I quickly came up with three answers, but then realised that they were all wrong.
September 23, 2011 at 7:40 am |
By Jeeves, I think I’ve got it
September 23, 2011 at 7:45 am |
Either I’ve got the wrong “answer” or the “answer” is wrong.
September 23, 2011 at 7:48 am |
Done about 10 seconds, although I can sense some objections coming on Monday
September 23, 2011 at 7:52 am |
Well it is approximately correct…
September 23, 2011 at 8:04 am
Indeed, the equation becomes closer to being correct than it is now
September 23, 2011 at 8:02 am |
Lovely Jubbly. Sweet as a nut… Sorted!
September 23, 2011 at 9:40 am
Yes, easy as….
September 23, 2011 at 8:07 am |
I’m not sure if the people saying they have a slightly incorrect answer are right. There is, to me at least, a very correct answer
September 23, 2011 at 6:59 pm
Then you don’t have the intended answer. But you still may have a good answer though…
September 23, 2011 at 8:41 am |
Bang. Sorted. Spent 5 mins staring at it, bought a coffee, and when I came back the answer jumped out like the bunny girl at the church fete.
September 23, 2011 at 8:50 am |
Ha, lovely one. Easy once you get it, totally baffling before that. I’m gonna pass this around at work today.
September 23, 2011 at 8:52 am |
Took me about 30 seconds to figure out what the probably “correct” answer is, although it’s only actually correct to two decimal places.
September 23, 2011 at 9:16 am |
mmm… I think there’s actually 2 correct answers
September 23, 2011 at 9:24 am |
Can somebody mail me the answer, please. It’s driving me mad.
mymonkeylife@hotmail.com
September 23, 2011 at 11:57 am
Did anyone email you an answer? If so, could you send it on to me, PLEASE? it’s driving me nuts and I want to inflict it on the children when they get home. X
September 23, 2011 at 10:22 am |
really really fast this week!
September 23, 2011 at 10:28 am |
Easy as pi
September 23, 2011 at 10:43 am
It wasn’t easy as pi for me, but I did get an A plus.
September 23, 2011 at 10:38 am |
Took me a few minutes, then suddenly got it.
Technically speaking though, the left half of the equation will be slightly larger than the right half of the equation (unless, as Fluffy says, you only do the equation to 2dp)
September 23, 2011 at 10:50 am |
As easy as pie. Guessed the correct answer, checked with calculator. Took seconds.
September 23, 2011 at 11:20 am
If you checked it with a calculator then that calculator is broken.
September 23, 2011 at 11:28 am |
Got it in under 5 minutes, though the math geek in me screams wildly at the resulting inaccuracy.
September 23, 2011 at 12:02 pm |
I think I’ve found the “slightly” incorrect aswer. It’s maths, people. the answer is simply incorrect; there’s no “slightly” in maths. There’s only equality and inequality. If this turns out to be the solution I’d be very disappointed in the good professor.
September 23, 2011 at 12:12 pm
I don’t think the ‘slightly” incorrect answer is the answer. There’s another answer I’ve found, which is correct, with no slightly about it. I think people found the first answer, assumed it was that and didn’t bother thinking anymore about it.
September 23, 2011 at 12:50 pm |
I found an elegant solution that doesn’t require approximation.
And yes, I also know the answer that Richard expects.
September 23, 2011 at 1:24 pm |
got it
around a minute
September 23, 2011 at 1:36 pm |
the puzzle clearly states that we must “make the equation correct.” not approximately correct, or correct to a certain number of significant digits, but correct.
there is a correct answer, although it’s inelegant for two reasons. but it does “make the equation correct.”
September 23, 2011 at 2:22 pm |
Super easy. Took me about 5 secs.
September 23, 2011 at 4:00 pm |
i did it approximately in just over 3 seconds. need a better answer tho….unless that is good enough for romans
September 23, 2011 at 4:12 pm |
I have one but it requires one very special knowledge… Don’t know how “common” that knowledge is though (but it should).
September 23, 2011 at 4:37 pm |
under a minute, because I was struggling with myself to reject my answer
September 23, 2011 at 4:55 pm |
Two minutes. I have AN answer which I think is pretty clever, but I don’t know if it’s THE answer.
September 23, 2011 at 5:06 pm |
I got an answer, but it’s missing a tilde.
September 23, 2011 at 5:14 pm |
I can make it “right” if I can break a matchstick in addition to moving one… thereby making Mark_D’s tilde…
September 23, 2011 at 5:57 pm |
Yea – spotted the ‘broken’ matchstick straight away – the ‘other’ answer isn’t right as it’s only an approximation!
September 23, 2011 at 6:01 pm |
The approximate answer came in about 10 seconds.
A more exact but “cheating?” answer came after a few more minutes.
I hope that neither of these are the preferred answer, and that I’m missing something.
September 23, 2011 at 7:18 pm |
Blinding light after about 3 min
September 23, 2011 at 8:05 pm |
Easy peasy.
September 23, 2011 at 8:10 pm |
Here’s my question … what if there were three matchsticks on the right side of the equation? That also has a move-one-matchstick solution.
September 23, 2011 at 9:00 pm |
Took about 1.5 minutes
)
September 24, 2011 at 1:46 am |
I think I solved it… But I hope that mine´s not the correct answer cause this would be a stupid puzzle…
September 24, 2011 at 1:50 am |
20 minutes !!!
September 24, 2011 at 5:22 am |
About 15 sec. Reflecting on my performance: a bigger gap between XX and iii would have made it easier.
September 24, 2011 at 5:32 am |
One Second.
I am going to bask in my own glory now
September 24, 2011 at 5:33 am |
Oh, maybe I have the wrong answer.
September 24, 2011 at 6:08 am |
OK I got an exact answer but I am not proud of it as it requires a bit of perversion of the Roman Numerals.
September 24, 2011 at 6:10 am
Took about 30 minutes.
September 24, 2011 at 10:10 am |
Ah, another one from the bumper book of my first puzzles. I couldn’t find a rational explanation.
September 24, 2011 at 3:56 pm |
I found the approximate answer and another answer that is exact but ends up with the ma thematic notation looking pretty funky.
September 24, 2011 at 7:42 pm |
Really not with this and have only managed to get answers by breaking the rules, no doubt on Monday I will be slapping my forehead in shame!!!
September 26, 2011 at 2:54 pm |
2 secs
September 26, 2011 at 9:24 pm |
Was thinking in terms of floor and ceiling function and then proceeded to square root. And that gave the beginning of how the matchsticks could be oriented. 5 minutes.
September 26, 2011 at 9:56 pm |
This was my 1 sec answer.
If you multiply between each “digit” you can get an exact answer. That took abou 30 min.