# Matchstick Problem: Turn 1 into 12 by removing a matchstick [closed]

Below are some matchsticks arranged to display an expression.

Your task is to remove one matchstick so that the resulting value of the expression will be twelve.

• Just to be clear. Remove--- not Move right? – DrD Oct 9 '20 at 18:10
• There are so many possibilities... – user69881 Oct 10 '20 at 2:25
• I love how many answers the people on this group have come up with to what is essentially an impossible problem! – Dr Xorile Oct 11 '20 at 18:04
• There seem to be a lot of different answers here, and no reason to particularly prefer any of them. (Several of the other answers seem more plausible than the accepted one.) – Deusovi Oct 11 '20 at 22:09
• @Deusovi Thanks,but I did not accept the answer just because I preferred it. I only accepted it because it was what I had in mind in the first place. – risky mysteries Oct 12 '20 at 0:47

Remove the top of the 7. The 8 can be viewed as 13, so $$13-1= 12$$. Which also means that you can make it equal to $$13-7=6$$ without moving any matches!

Demonstration:

• "Without moving any matches" yet you had to move two matches to make it work! – Weather Vane Oct 13 '20 at 18:22
• Next puzzle: Turn 8 into 13 without touching anything – Helena Oct 20 '20 at 16:37

Here is another fairly lateral one:

If we interpret "-" as difference of shapes then the result is a small "c" which is, of course, the hexadecimal for 12.

• difference of shapes, hexadecimal, you seem to have very flexible interpretation of the assignment ;-) – Tomas Oct 11 '20 at 20:49
• @TMS Don't say flexible, please. I prefer the word "lateral" ;-) – Paul Panzer Oct 11 '20 at 22:20

Possibly a little too lateral but if we

Remove the middle match from the '8' to make a '0'

And then

Look at the image inverted

We get

which could be interpreted as

L - 0 = L and since L is position 12 in the alphabet, this can be interpreted to evaluate to 12.

• But, but, but... if the left is an L shouldn't the right be an O (the letter, not the digit)? – Paul Panzer Oct 9 '20 at 23:32
• I also had this idea, but usually people would use $A$ for $10$, $B$ for $11$, etc. – WhatsUp Oct 9 '20 at 23:33
• @WhatsUp Actually, my first inclination would be that L=50 – hexomino Oct 9 '20 at 23:34
• @PaulPanzer Nah man, it's clearly a 0. – hexomino Oct 9 '20 at 23:35
• Actually, the more I think about it the more I like it. The "-0" does a decent job of killing the L=50 association. This almost resembles something intentional ;-) – Paul Panzer Oct 10 '20 at 0:22

A bit of a stretch, but here goes:

The only way to read the thing on the left as a number is as a 1 and a 9 who haven't heard about social distancing rules. So that will read 19-7.

• It just looks like an "A" to me – bobble Oct 9 '20 at 23:00
• @bobble Just squint a bit ;-) --- I said it was a bit of a stretch. And I wouldn't have posted this if the other answers were any more compelling. – Paul Panzer Oct 9 '20 at 23:04
• So your final result is $3$... Also you don't have to remove any stick to read it as $19$. – WhatsUp Oct 9 '20 at 23:11
• @WhatsUp The point is that with the bottom in place there is no reason at all to read it as anything but an 8. With the stick removed I can't think of any plausible way of reading this as a number other than the one I suggest. – Paul Panzer Oct 9 '20 at 23:18
• You could read it as "1 - 7" just as easily as "19". – chepner Oct 10 '20 at 18:47

Invert the image
Remove the match which is (now) bottom right

This leaves two characters L and @
In ASCII encoding, the difference in their values is $$12$$

Similar to other answers, but "sticks" to a single coding scheme.

Remove the lower-left stick on 8.

Japanese borrowed the English word dozen as ダース (dāsu). Remove the bottom left match and you get:

 _ _ |_| _ | | | | 

which is ダース in a rather crappy low resolution font (especially the su is really ugly)

• That can by no means be read as a ス. Anybody would rather call it a フ. Also you are missing the two dots, which are crucial. So basically you created a ターフ – WhatsUp Oct 9 '20 at 19:52
• @RadovanGarabik Cool! – risky mysteries Oct 9 '20 at 19:55

My swing at it:

Remove the middle bar from the 8. It’s now D hexadecimal. Minus 1 is C which is 12 base 10.

In very lateral thinking, let "remove one matchstick" be interpreted as "re-move one matchstick", which means to move one matchstick again. So move the top right matchstick to the windowsill. Then re-move it to the middle of the puzzle so it reads B + 1, which in hexadecimal is 11 + 1, which is 12.

Remove the middle stick on the left. Then you get "0 - 7" which equals 12 (mod 19).

• Can't understand how this is correct if we are taking mod $19$ like that way. – Anonymous Oct 11 '20 at 4:29
• @Anonymous Minus seven is congruent to twelve mod 19. – Rand al'Thor Oct 11 '20 at 6:45
• It is, but why are we considering mod? in that case I would solve most of the matchstick problems like this, taking mod of a certain number, in this case, 19 – Anonymous Oct 11 '20 at 8:57

Move a stick from 8 and place it over '-' to make a '+'.

Next remove a stick as shown to get 5+7=12.

• If you are are allowed a preprocessing step, you could simply rearrange the matchsticks all you like before removing one. – chepner Oct 10 '20 at 18:48