# Unexpectedly Difficult Matchstick Problem

The words say:

note: it is not my puzzle and i do not know the solution

• welcome to puzzling se – Oliver Ni May 10 at 7:11
• Are we allowed to rot13(cynpr n zngpu bire gur rdhnyf fvta ng na natyr gb znxr gur "qbrf abg rdhny" fvta)? If so, there are several solutions. – Lanny Strack May 10 at 7:15
• @LannyStrack if that were the case, this would be a very dull puzzle. Not sure if there are any actual solutions besides that, working on it – Oliver Ni May 10 at 7:19
• @OliverNi - It is not unheard of to have a trick question whose answer is dull (once you know the trick). – Lanny Strack May 10 at 7:19
• If you tried to solve this on an internet site with cookies then it tells advertisers you are someone who has a) time to waste b) you are a problem solver rather than a manager or something, therefore probably earning enough c) you are motivated by proving your intelligence. The correct answer therefore depends on what kind of ads you want to pop up everywhere when browsing the web. – Frank May 11 at 9:26

Remove the top left match of "9". Then the "9" becomes a "3". Place the removed match horizontally before "3". Then, it becomes "-3".
So, our equation becomes
-3+5=2

• I like that better than my answer. – Lanny Strack May 10 at 7:26
• Nice! how did i not see that?? – Oliver Ni May 10 at 7:27
• Congratulations @Sid. 200 IQ! – DrD May 10 at 12:49
• My solution was to take that one and put it over the equal sign, changing it to "not equal," but I like yours better. – Cristobol Polychronopolis May 11 at 16:52

Move the top-right vertical match in the 2 to the top-left vertical position so that the right hand side forms an 'E'. The equation then becomes 9 + 5 = E, where E is 14 in the hexadecimal number system. 9 and 5 are represented the same in both decimal and hexadecimal, so the left hand side of the equation is unchanged.

• Found the computer nerd :-) – Carl Witthoft May 12 at 12:58
• Definitely a +1 from me mainly because my first answer on the site also involved matches and a sneaky abuse of hex :) – ElPedro May 12 at 17:03

You can also

remove the vertical match from the plus sign and place it slanted over the equals sign to get $$9-5\neq2$$.

• the question does say "satisfy the equation" – Agnishom Chattopadhyay May 11 at 2:23
• The translation provided with the question does say "equation", but Google Translate says "算式" is "formula", so, if this is correct, I would say this answer qualifies. – dhag May 12 at 14:21

I am not sure if this is what the puzzle creator has in mind, but if you:

discard the match in the upper left (e.g., "moving" it by striking it so that it lights and then burns up), and then rotate yourself behind the puzzle looking at it upside down (equivalent to flipping the puzzle around an imaginary x-axis), it reads 3+2=5.

• rot13(Ybbxvat ng vg "sebz oruvaq" [fhpu nf sebz gur obggbz bs n tynff gnoyr] jba'g jbex orpnhfr gur 3 orpbzrf na R. Ohg hfvat n zveebe fubhyq jbex) – BlueRaja - Danny Pflughoeft May 10 at 19:44
• @BlueRaja-DannyPflughoeft - that is not what I wrote. Read the full answer. – Lanny Strack May 10 at 22:08
• wouldn't the 3 be backwards? – Swiss Frank May 11 at 3:03
• @SwissFrank - no. rotate it 180 degrees on the x-axis. still forwards. – Lanny Strack May 11 at 6:16

Another [lateral-thinking] option is

Tilt the upper match of the equals sign, making it into a greater than sign

• You beat me to it! This was the solution I saw. – Paul Chernoch May 11 at 13:03
• The question does say "satisfy the equation". – pts May 11 at 23:41
• I'm probably going to regret asking this, but my mind is blanking. What's it called if you're not using "="? i.e. "9+5 > 2" ....... Is that a statement? or formula? What if you moved the left-top of the 9 to get "3+5 >= 2" (use imagination for >= as one sign please) - is that an equation? or a statement? (or whatever word I can't think of..) – TCooper May 12 at 20:30
• @TCooper "inequality", although the starting "statement" is not already an inequality. – user170231 May 12 at 22:05

I’m thinking hexadecimal here. Therefore 9+5=E, in Base16. >!One matchstick from 2 to E.

• Welcome to Puzzling.SE! I'm afraid somebody already beat you to this answer: puzzling.stackexchange.com/a/98050/31839 – F1Krazy May 12 at 10:59
• That’s cool, just wanted to participate. My first time here in this particular community. – Joey Godwin May 12 at 11:08
• @JoeyGodwin please "spoilerize" any answer you post in this group. See the "help" section for formatting tips – Carl Witthoft May 12 at 12:59

I saw this once and a solution I saw was

Remove a match from the 9 to make it a 3. Then put that extra match over the equals sign to make a not equals sign (≠)