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.
782
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Justifying a redouble
This puzzle is derived from a real game of bridge I played on Bridge Base Online.
I was sitting North on board 9 (N dealer, E-W vulnerable) and the bidding turned out like this:
West
North
East
South
...
- 6,954
0
votes
1
answer
137
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Techno-Culinary Brain Teaser: Unravel the Code in the Kitchen
The answer is one word.
The rebus:
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0
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115
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4
votes
1
answer
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Find the ciphering method 2
Link to the entire series.
The message:
3, 53, 48751, 9247757, 294914580539
The answer is a 13 letter word: UNDERSTANDING
Hint 1:
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2
votes
1
answer
255
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Find the ciphering method using deciphered message
Link to the entire series.
Ciphered message:
...
- 425
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0
answers
73
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Find the largest number with unique digits, that is divisible by each of its digits [duplicate]
Find the largest number with unique digits, that is divisible by each of its digits.
For example 132 has unique digits and is divisible by 1, 2 and 3. But it is not the largest such number. Can you ...
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31
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13
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2 vs. 1.005^200
Without using a calculator or a computer can you determine which of these two numbers is bigger: $2$ or $1.005^{200}$ ?
I saw this puzzle in a YouTube video, which I will post later.
- 31.6k
-2
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1
answer
114
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Fill a 4x4 grid with minimal sum of positive integers in a way that adjacent cells contain numbers of different parity
Find a 4x4 grid containing 16 unique positive integers with minimum sum, such that adjacent numbers have different parity.
- 425
6
votes
1
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The Nine Gardens Of Eden
This puzzle is part of the Monthly Topic Challenge #11: Now in 3D.
There are nine distinct known three-cell Garden of Eden patterns in the Life Without Death cellular automata, including the two well-...
- 2,699
1
vote
1
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255
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A take on custom ciphers
There is something hidden in the text below. Can you find out what it is? Note: no computers or tedious work required.
...
- 701
12
votes
3
answers
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I Hate Traffic And So Do You
I need to travel through the city from my house to school, but the traffic is horrible right now.
I can only move along the city's grid with the following conditions:
• blocks with traffic (marked in ...
- 574
2
votes
1
answer
247
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The minimalist game master [closed]
A game master tells his party of players that he has converted to the school of minimalism, and is going to do away with all of his dice in the campaigns they play from now on. In the place of dice, a ...
- 2,172
0
votes
0
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149
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Puzzle "railway game set"
Alisa completes a railway game set which allows us to make various closed railway routes with crossroads. It is need to put the “rails” parts in the kit, as well as four types of “crossroads”: corner (...
- 1,699
-3
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1
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Giraffe Necked Island
Where is this island, and why is the title of this question "Giraffe Necked Island?"
- 321
4
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1
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294
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A different Crack the Code puzzle
This is a different Crack the Code and get the word puzzle. Here, instead of letters, actual words are hidden.
The final word is a 7 letter famous person. That word consists of several words. I only ...
- 4,641
3
votes
1
answer
351
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Micropoker: small hands on deck
Raise your hand if you are ready for micropoker,
which minimalistically resembles
5-card poker.
The deck has just 8 cards with 2 suits of 4 cards each.
A hand is dealt as 3 cards that are final, with ...
- 21.8k
20
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7
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1k
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Save now! All the digits at half the price
... or double the price depending on where you're coming from
Consider the set $PD10$ of pan-digital ten-digit numbers, i.e. positive whole numbers whose decimal representation has each of the digits ...
- 18.2k
8
votes
1
answer
1k
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Important Alien Message
A strange alien transcript, alongside what is believed to be a partial key, was recovered the other day. Scientists aren't sure what the message might contain, but theories point to some sort of ...
- 529
13
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1
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Find the lower 8-digits number such that
This one come from newspapers in France, where this week is the "mathematics week", and some problems are proposed to kids.
This single one is easy and funny:
Find the lowest 8-digit number, ...
- 1,424
10
votes
1
answer
292
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Equilibrium of differences
There is a subtraction equation written on the board, with three digits minus three digits, and the first digits both fixed. Alice and Bob need to fill in the remaining 4 digits (A~D below) using 4 ...
- 802
10
votes
1
answer
745
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Numbers whose product of digits is a multiple of sum of digits
Find three consecutive numbers, greater than 10 and none with a digit 0 in it, each of which is such that the product of its digits is a multiple of the sum of its digits.
What about four or more such ...
- 16.8k
3
votes
1
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347
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How to find the value that makes this addition equation work without using a computer?
The following image represents the addition of 2 five-digit numbers, where 10 different letters represent 10 different numbers (0~9). What does PUZZLE equal? (There are two possibilities and a ...
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12
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1
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Friends and Enemies
Here is a short puzzle I made:
There are 10 people arranged in a row, and each of them has a friend and an enemy also present in the row. Your goal is to identify the friend and enemy of each person.
...
15
votes
1
answer
526
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What does the fox say?
I found a piece of paper on the hallway floor of my friends apartment complex, and on it is an oddly written question and an unreadable response. Can you figure this out?
Question:
WHAT DOES THE FOX ...
- 2,438
15
votes
1
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Trust me: you do not want to go down this road with me
Every cell has a digit from 0 to 9 or one of the four operation symbols +, −, ×, and /, signifying addition, subtraction, multiplication, and division respectively.
No digit appears more than once in ...
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3
votes
1
answer
247
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Two many restrictions
Using only the number 2 several times, form the numbers 2, 22 and 222.
The following operations are available:
addition
subtraction
multiplication
division
exponentiation
Each of these operations ...
- 2,584
5
votes
1
answer
319
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What is a Nature Word™?
This puzzle 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 Nature Word™.
...
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What season was it?
A puzzle maker wrote this in his notebook as a holiday puzzle:
Th bbie sartd unning.
What season was it?
- 455
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3
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510
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125034 v1.0.0 / WR 1713-11-07
I am developing an app that generates puzzle games every day (https://125034.pages.dev/).
Their basic form may be viewed as Wordle in math, Sudoku in 6 grids, or Einstein's Riddle in 1 row.
If today ...
- 13
28
votes
2
answers
2k
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A logician's Bingo
Mark some cells on the following Bingo board, so that all statements in marked cells are true AND all statements in unmarked cells are false.
A Bingo here is a set of five marked cells in a row, ...
- 11.5k
5
votes
3
answers
416
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Laziest Checkmate
Consider a game of chess where White delivers checkmate in their $X^{th}$ move. For all the pieces that remain on the board at the end of the game, consider their Manhattan Distances from their ...
- 2,584
4
votes
1
answer
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Packing the Primes
Here is a 5x4 rectangular wordsearch (area 20) containing the primes between 1 and 100,
{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}
(numbers in any ...
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The Universe's Secret
To find the universe's secret, first solve the Sudoku variant with #s 1-7 only.
No number may be repeated on any diagonal. No numbers go in the squares with red or green dots.
Then use the solution ...
- 17.5k
5
votes
6
answers
412
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How many digits does $7^{100}$ have?
I'd like to estimate $7^{100}$ without using these new-fangled computers everyone is talking about, but I think I need your help.
Please estimate $7^{100}$ without the use of a computer. My friend ...
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15
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The computer can't do anything I couldn't do with pen and paper
If you want to know how much $3^{100}$ is, you can just type it into a computer and it will spit out a really big number. But that is no fun. The task is to estimate $3^{100}$ with some computation ...
- 1,309
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2
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A square number that is a concatenation of at least 25 squares
A pen and paper challenge:
Write down a number whose square (repetition allowed) is the concatenation of at least 25 nonzero squares.
examples
7, 13, 12: Their squares are the concatenation of 2 ...
- 7,609
1
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1
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Determine the hidden digits in this long division puzzle
The following problem was given in the Eureka journal (October 1963/University of Cambridge). This problem can be solved by hand without computers. There is a unique solution. Have fun solving!
Fill ...
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votes
2
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What is my favorite brand of pen?
This is an entry to the Monthly Topic Challenge #3: Pencil and Paper Games
Given the following valid "tic-tac-toe" boards:
What is my favorite brand of pen?
Other possible tags to check ...
- 23.1k
5
votes
2
answers
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a six-by-six KenKen
The rules of KenKen are as follows:
You must fill in the numbers 1 through 6, one number per box, in the grid, so each row and each column contains each number exactly once.
Each heavily outlined ...
- 11.7k
4
votes
2
answers
424
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Dark time in prison
You wake up. It is pitch dark. You don't know where you are. You feel groggy.
The last thing you remember is being in a bar, a sexy young woman appeared out of nowhere, walked straight at you, ...
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6
votes
2
answers
1k
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What are the hidden digits in this long division puzzle?
The following problem was given in the Eureka journal (April 1978/University of Cambridge). This problem can be solved by hand without computers. There is a unique solution. The phrase, "exact ...
- 4,403
3
votes
1
answer
204
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Sequence of numbers - what comes next? [duplicate]
What is the next number in this sequence, and why?
4 2 3 4 6 2 4 8 3 _?
Also, since people here find sequence questions to be arbitrary, the following uses the same rule. What number is next?
4 5 6 4 ...
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3
votes
1
answer
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Tetromino tilings of a 4x5 rectangle with minimal diversity
This is a relatively easy manual tiling puzzle. In fact the tiling is all done for you, you just have to specify how many of each of the 26 given tilings to use. The puzzle is:
Using N complete sets ...
- 3,762
6
votes
1
answer
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Find all integers n such that $\sqrt{n-4 \sqrt{n-19}}$ is also an integer
The following puzzle is from the December 2012 issue of the Eureka journal (published by The Cambridge University Mathematical Society).
Find all integers n such that $\sqrt{n-4 \sqrt{n-19}}$ is also ...
- 4,403
13
votes
1
answer
2k
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The Lufthansa Lottery
In order to pass free time while striking for better pay, some Lufthansa workers organise a lottery where
each ticket picks three distinct numbers from $1$ to $11$ inclusive
the draw picks five ...
- 6,954
17
votes
7
answers
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Efficient Mowing at PSE
Your task:
Find the most efficient mowing path around the dark green bushes that mows (passes over) all of the grass (light green).
For those who cannot view the image above, there are 9 rows of 16, ...
- 17.5k
13
votes
4
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785
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How do I create a sliding-blocks puzzle (specifically like the "Rush Hour" ones) which requires an "ah-hah!" moment?
Background
My grandma gave me a set of Rush Hour puzzles as a small child, ever since I could be trusted to not eat the pieces. I still enjoy playing these today and would like to try my hand at ...
- 10.1k
4
votes
1
answer
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Find the 3 Item Amounts
Last week the store's receipt printer removed lines randomly from each item amount.
A technician repaired the printer, but now it adds lines randomly to each item amount!
The cashier told me that for ...
- 17.5k
18
votes
3
answers
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Find the Two Item Amounts
I bought 2 items yesterday and the receipt was incorrect, so I asked the cashier about it.
She told me that
The receipt printer had been acting funny recently.
The total is always correct, but some ...
- 17.5k
6
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1
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Riley-Clued Crossword
The no-computers tag is there only to prevent database dictionary searches. Other computer uses are fine.
Below is an ascii version of the image above, for those who cannot view images. All words are ...
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