Questions tagged [no-computers]
A puzzle designed to be solved without using calculators, online decoders, or computer programming. Using a computer to type and post the answer is allowed; the spirit of this tag is to make people solve the puzzle on their own.
936 questions
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A Logic Puzzle Where No Variable Can Be Determined Without All Six Clues
Six variables ๐ด, ๐ต, ๐ถ, ๐ท, ๐ธ, ๐น are distinct integers from 1 to 10 (inclusive).
They satisfy the following conditions (I've added mathematical definitions on the right to avoid ambiguity):
๐ต is ...
- 491
8
votes
4
answers
691
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Six-Variable Logic Puzzle - How to solve with a forced logical path
Six variables ๐ด, ๐ต, ๐ถ, ๐ท, ๐ธ, ๐น are distinct integers from 1 to 10 (inclusive).
They satisfy the following conditions:
๐ด ร ๐ต = 24
๐ต is adjacent to ๐น โ |B-F| = 1
๐ธ โ ๐ท = 3
๐ถ is the ...
- 491
5
votes
3
answers
246
views
Find all (a,b) such that sum of factorials of each digit of a is equal to b and sum of factorials of each digit of b is a
Find all (a,b) such that sum of factorials of each digit of a is equal to b and sum of factorials of each digit of b is a.
How can you find all such numbers? Are there finite or infinite of such ...
- 2,447
2
votes
1
answer
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Find all integers a and b such that multiplying a by b literally is equal to aยฒ
Find all integers a and b such that multiplying a by b literally is equal to aยฒ.
When I saying multiplying a and b literally, it is as if were you are concatenating the product of each digits of a by ...
- 2,447
10
votes
2
answers
729
views
Can you make all the dominoes horizontal?
A 6x6 checkerboard is tiled arbitrarily with eighteen 1x2 dominoes. A new square is added to the right-hand side of the board, making the top row length 7.
At any time you may move a domino from its ...
- 35.1k
14
votes
2
answers
1k
views
Smallest number that is not a sum or difference of two palindromes
What is the smallest positive integer that is not the sum or difference of two palindromes? No computers please.
11
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4
answers
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A six-variable math-logic puzzle with a unique solution
My original puzzle: Six variables ๐ด,๐ต,๐ถ,๐ท,๐ธ,๐น are distinct integers from 1 to 10 (inclusive).
They satisfy the following conditions:
B - D = 2
F + A = 11
A is between D and C
No two ...
- 491
12
votes
6
answers
1k
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Add parentheses to make the biggest possible value
Maximize the expression below by inserting parentheses.
No other changes are allowed.
2 รท 2 - 3 รท 3 - 4 รท 4 - 5 รท 5
Attribution:
Quantum Magazine, March/April 1999
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45
votes
2
answers
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How many ways to tile this shape with dominoes?
In how many different ways can this shape be tiled with dominoes? This is one of the possible ways:
- 958
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votes
1
answer
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Find the value of n in the product without using calculators
If $n\times\lfloor\dfrac{n}{2}\rfloor\times\lfloor\dfrac{n}{3}\rfloor\times\cdots\times\lfloor\dfrac{n}{x}\rfloor=$ ...
- 2,447
9
votes
2
answers
735
views
A flea moving on a unit disk
Points A, B, C are evenly spaced on the perimeter of a unit disk. A flea starts at an arbitrary point P0 on the disk. It jumps halfway to whichever among A, B, C is the furthest away. It repeats this ...
- 6,564
-11
votes
3
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406
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Make 24 using 1, 3, 4, 6 [closed]
Make 24 using exactly one each of 1, 3, 4, 6, where the order of the digits does not matter.
Each expression is to be formed by using exactly one each of 1, 3, 4, 6 (and the allowable
operations ...
- 2,664
2
votes
3
answers
428
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-4
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1
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A City Name Game
MAIL = LIMA
ANIMAL = MANILA
PAIRS = PARIS
THEN
GOALS =
TORCHERES =
AGONISED =
ALMOST. =
AVENGE =
ANTIAR =
OARSMEN =
ASLOPE =
Please no computers and no partial answers.
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PSE Advent Calendar 2025 (Day 3): A gift from my travel agent
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2025. The accepted answer to this question will be awarded a bounty worth 100 reputation.< Previous Door Next Door >
My travel ...
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