Unanswered Questions
98 questions with no upvoted or accepted answers
22
votes
0
answers
3k
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What does this mathematical operator do?
The solution to this puzzle is one I came up with when working on this puzzle: What is the answer of this math puzzle?
For two natural numbers a,b, can you figure ...
- 660
22
votes
0
answers
2k
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REALLY important days in history
@Z. Dailey asks a mathematical puzzle Important days in history... and to come! with a series of dates in years 1973, 1978, 1983, 1992, 2005.
My puzzle asks the question: What is the previous date in ...
- 197
14
votes
0
answers
1k
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12
votes
0
answers
454
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Can we find four identically colored numbers?
Take the positive integers {1, 2, 3, ...} and color them red, green or blue. Is it true that no matter what coloring is chosen, we can always find three distinct numbers x, y and z so that x, y, z ...
- 16.2k
12
votes
0
answers
259
views
The Snake and the Hunter
The Snake and the Hunter is a game for two players who play in two rounds interchanging the roles of snake and hunter. The game is played in a rectangular grid of points, say 6×6. In both rounds the ...
- 19.3k
12
votes
0
answers
896
views
Dissecting a figure into 2, 3, 4, and 5 parts but not 6
This figure is divided in 2, 3 and 4 equal parts of same size and shape, but it is not possible to do it in 5 equal parts of same size and shape.
Is it possible to find a figure that can be divided ...
- 886
11
votes
0
answers
406
views
What is a Freecell Word™?
This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.
If a word conforms to a special rule, I call it a Freecell Word™.
Use the ...
- 11k
10
votes
1
answer
752
views
Powerful number systems
Imagine I have two positive integers, $a$ and $b$. Can you find the last digit of the sum $a+b$ given only the last digits of $a$ and $b$? More generally, can you find the last $n$ digits of $a+b$ ...
CommunityBot
- 1
10
votes
0
answers
512
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I'm a number with a special product, so name me when you think you've got it
In the blocks that come before,
their special product tells us more.
To guess my scheme you'll need calculation,
but only little tests of recreation.
Each block contains atoms strong as Thor,
...
- 2,296
9
votes
0
answers
361
views
A Glutton and a Split Check
N, T, A, B are arbitrary constants in this problem. I have only definitively solved the N=1 subproblem, so, if the general problem cannot be solved, I will be satisfied to mark as accepted a solution ...
- 2,389
9
votes
0
answers
476
views
The highest poem
I am three, often a person, always a digit, and also witout.
George POUST was his name.
Manufactured by Ford between 1972 and 1976.
YMCA was not my first team in my coaching career.
Theory of ...
- 11k
9
votes
1
answer
2k
views
Is there another name for this puzzle? (Kyudoku, Nine Find)
Is there another name for this type of puzzle? I can only find two examples of it online:
https://www.brainzilla.com/logic/kyudoku/
http://ninefind.com/
In the game you start with a 6x6 grid filled ...
CommunityBot
- 1
8
votes
0
answers
277
views
Doubling the cube with rational Meccano strips
In three monographs published in 2006, 2008 and 2014 Gerard 't Hooft considered "Meccano mathematics": how to construct specified distances and regular polygons by a rigid system of ideal ...
- 7,820
8
votes
0
answers
229
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There are 49 cards here. Figure out what the seven facedown cards are and what position they're in
So here's the problem
"There are 49 cards here. Can you figure out what the seven facedown cards are and what position they're in?"
I have tried about everything in my math tool belt to try ...
- 10.3k
8
votes
0
answers
201
views
Is it possible to create a knot that is locked only when the rope is stretched?
Is it possible to create a knot that is stable/locked when the rope is stretched?
When the tension is relived the knot should open.
- 8,333