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Rewriting the puzzle in text:
Move exactly 2 matchsticks to make this equality true:
4 + 9 - 7 = 1
- By the word 'move', I would also like to allow the possibility of 'remove', to allow for additional creative solutions.
- You can use both operations, move and remove, in your solution, but the total number of matchsticks which you move or remove should be 2 only.
- That is, you can do one of the following alternatives:
- 2 move operations
- 2 remove operations
- 1 move and 1 remove operation (in any order)
- The equality must not be converted into inequalities. Please don't modify the equality symbol.
- Please do not introduce more matchsticks into the puzzle.
- I don't have a full list of solutions.
asked Jul 23, 2021 at 17:34
21311 silver badge66 bronze badges
OP explicitly forbids tinkering with the given equals sign, but
nothing is said about adding a second one.
Therefore, moving two:
-4 + 5 = 1 = 1
Similarly, removing one and moving (or rather just very slightly nudging) one:
-1 + 9 - 7 = 1
And a third one (move two):
11 + 3 - 7 = 7
answered Jul 23, 2021 at 20:35
loopy waltloopy walt
16.9k2626 silver badges8080 bronze badges
By removing matchsticks:
Pick up the horizontal matchsticks at the top and bottom of the 9, leaving 4+4-7=1.
answered Jul 23, 2021 at 17:38
Nuclear HoagieNuclear Hoagie
3,8011212 silver badges2828 bronze badges
Here's another solution, by moving two times.
answered Jul 23, 2021 at 18:14
23.6k44 gold badges1212 silver badges105105 bronze badges
1 + 9 - 9 = 1 (move two left-most from 4 to make 1, add two to 7 to make 9)
7,62211 gold badge2929 silver badges6161 bronze badges
answered Jul 25, 2021 at 7:42
4111 bronze badge
Another solution that moves two matchsticks:
-4 + 6 - 1 = 1 (Convert the 9 to 6, and use the top of the 7 to make a negative sign)
answered Jul 24, 2021 at 7:20
1,17777 silver badges1212 bronze badges
9 - 9 + 1 = 1 (move the vertical matchstick from
4 to make a
9 and then move top horizontal matchstick from 7 to change the second
- into a
answered Jul 25, 2021 at 13:33
2122 bronze badges