The above illustration depicts an invalid Roman numerals equation (the left side is 6 and the right side is 2) using seven matches. Find a way to correct this equation by only moving one match. You cannot shift the position of the other matches.

## Solution (Click to Show)

As is equal to 1, the equation is now valid.

If you have read my previous post about Henry Ernest Dudeney’s ingenious match puzzle, you won’t have much problem answering this. After all, the methodologies for solving these two puzzles are almost the same.

Dudeney’s puzzle was my inspiration when I came up with the puzzle for this post. I believe that my puzzle is easier than Dudeney’s, though a friend did not agree. He said that my puzzle would only be easy for someone who’s already familiar with Dudeney’s version.

Very interesting. I am not a mathematician, therefore the answer is in the solution. I am OK with it though. Great post.

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My best guess was move the first match slightly to the right to make XI = 11. Just a bit of a cheat 😛

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Cool. That’s technically acceptable.

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I would’ve moved one match and put it on top of the equal sign to make it a ‘not equal’ sign. Thought my answer was clever till i saw the correct one lol

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Good one, but way to hard for me.😊

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I can see my name equal to 2 hahaha

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:)

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My husband’s solution: VI > II

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Would it have been fair also to move one perpendicular match diagonally across the equal sign to show that 6 does not equal 1 or 5 does not equal 2?

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If the puzzle doesn’t strictly require it to be an equation, then yes.

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monkey have other answer what little bit dodgy because it produce valid math sentence but not produce equality. move vertical match on left side so it lay across equal sign. new math sentence say “five not equal one.”

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I did the same.

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I went down that route too, five doesn’t equal one.

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Actually Mr Sock Monkey, your solution uses exactly the same mathematical language as the original puzzle, because, while it shows 6 equals 2, in order to read it correctly, you have to say, “6 does not equal 2”. I came up with the same answer you did, though technically it’s “five not equal to two” or alternatively “six not equal to one”. Much better than getting involved with square roots !

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The puzzle requires an equation, not an inequality. Nonetheless, as I said to monkey, I like this way of thinking.

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eyeball of monkey not work well today. new math sentence really say “five not equal two.”

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I like your way of thinking.

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Tricky one today – for me at least! I hadn’t seen the Dudeney one though.

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