# 9-5=5? Matchstick problem

Move one matchstick to make an equality.

Question made by me (Is this too easy?)

• First idea was: 9 - 5 < 5. But I believe your request of an equality wouldn't allow this inequality. Jun 3, 2020 at 9:07
• @SwissFrank: To be honest I would also count that as requiring two moves, one for each of the = matches since you need to rotate both. Jun 3, 2020 at 10:50

Here's one way:

For the image-impaired:

5 = 5 = 5

• Congrats! You earned Enlightened, Good answer and, Nice answer for answering this question! Jun 2, 2020 at 5:00
• Technically, that is not "a correct equation", but rather, a few correct equations... Jun 2, 2020 at 13:12
• But the two = signs are not at the same height... I dismissed this solution in my mind, since I'd have to move two matchsticks to make the = match the other =. @ScottMiller's solution should be the accepted answer, since it is truly moving only one matchstick to make an equality (although, it's definitely not "easy"!).
– LHM
Jun 3, 2020 at 21:20

Another solution:

• Love it. I found the easy one and move on... this is next level creativity though, well done. Jun 3, 2020 at 2:56

Another solution is to

move the center bar of the 9 to the lower left position of that digit to make a 0

and then

look at it from the other side of the table (i.e. rotate it 180 degrees), so it appears to say $$5=5-0$$

• Isn't doing the second part of that equivalent to moving all of the match sticks? Jun 1, 2020 at 22:34
• Not if they're on a flat table. Jun 2, 2020 at 1:31
• @KevinWells: It depends on how much the puzzle constrains lateral thinking. Free rotations is usually not in the spirit of these puzzles but I wouldn't blanket exclude lateral solutions either as they are an interesting style in and of themselves. Jun 3, 2020 at 10:51
• @Flater I would expect that kind of question to include the lateral thinking tag, but I get that some people prefer to look at all puzzles through that lens Jun 3, 2020 at 18:40

One more possibility:

Move the upper-left stick of the 9 to cross the equals sign so we get 3 - 5 ≠ 5

• You should not use the answer unequal sign. Jun 2, 2020 at 1:07
• The answer specifically says "equality"... that wouldn't be an equality... Jun 3, 2020 at 9:04

This is the first thing that came to mind (when the question was originally posed as "Move one matchstick to make an equation"):

Written out:

5 - 5 ≠ 5

• Seems like you notice the word “equality”. You formed an inequality. Jun 2, 2020 at 3:16
• @CulverKwan: I don't see the word "equality". I see the word "equation". I've always considered inequalities to be equations, as you can still manipulate them using the same rules. Most of the internet seems to agree with you, but if I've ever heard this distinction, I don't remember it. My concept was to move the bottom bar of the 9 to form a not-equals sign, and there's another version elsewhere, so apparently at least 3 people on Earth think of this as an equation. Jun 3, 2020 at 2:12
• @MichaelS, I will edit the question. Jun 3, 2020 at 2:13

You can also make it:

9-4=5

just by

moving the top match from the first 5

• You would need to move the bottom one too. Jun 2, 2020 at 14:29
• It would still be readeable with the bottom one there, at least in my opinion. I think there are a bunch of answers to this. Jun 2, 2020 at 14:38
• It may still be readable but IMO the "4" with a bottom bar is not a number. When have you ever seen a 4 drawn with a bar on the bottom? Jun 2, 2020 at 21:13
• image.freepik.com/free-photo/… Jun 3, 2020 at 13:14

I'm not familiar with the process by which y'all are rendering these (some type of MatchstickML based on TeX and MathJax?) But as there is no specified alignment and you assume they may only be vertical or horizontal, if you move the \U+002D matchstick to the initial 9, one could consider that that a crossed or dotted zero, (as all zeros should be), leaving something akin to

0̸５＝𝟻

(Something akin to padding a simple 8-bit decimal in UTF-16 with a BOM, for ridiculous encodings like that.

P.S. I'm honounered to be Lizzy, but where's Colonel Brandon?

• No, it is to complicated. Jun 3, 2020 at 0:51
• "I'm not familiar with the process by which y'all are rendering these (some type of MatchstickML based on TeX and MathJax?)" These are all just plain old images, created probably with something like Paint. Jun 3, 2020 at 13:00