Questions tagged [no-computers]
A puzzle designed to be solved without using calculators, online decoders or computer programming.
507
questions
4
votes
1answer
170 views
Put the numbers $1, 2, …,16$ in circles
Put the numbers $1, 2, 3, ..., 16$ in circles so that the sum of the four numbers on each side of the triangle should be equal.
6
votes
1answer
225 views
A new year's mathematical mystery
Sam, Magnus, and Olivia each try to write the number 2020 as the sum of consecutive positive integers.
They each use more than one integer, a different number of integers to the others, and none of ...
0
votes
0answers
175 views
A Logician's Game of UNO Flip
Two players are in the middle of an ongoing one-on-one game of UNO Flip, with all its standard rules in effect.
Play is currently Light Side Up. It is Player B's turn. Player A has 3 cards remaining, ...
14
votes
2answers
1k views
Make a hexiamond star by hand
Using some or all of the hexiamonds (pictured), make a star. You may flip pieces. The usual tiling rules apply, no overlaps, no gaps. Use only one or none of each piece. Answer is unique. Target shape ...
5
votes
1answer
838 views
And another one bites the dust
I recently found an extraordinary moremover online today. Have fun finding the solution!
It’s White to move and mate in 19 moves!
Bonus: Explain the title in relation to the solution!
Jozef Lozek, ...
5
votes
1answer
107 views
Sum of All the Others
There are ten different 10-digit decimal fractions, one of them being equal to the sum of the other nine. If each number has 10 unique digits, not counting the 0 before the decimal point (for example ...
1
vote
1answer
102 views
Confusing letter
I once received a letter where all letters of the alphabet was shuffled around.
The task was then to find out what each letter was and then read the letter.
I wrote a little letter for you:
Be ...
-2
votes
1answer
104 views
123456789 = 100 with three operations? [duplicate]
Given the sequence 123456789
You can insert three operations (+,-,X,/) into this sequence to make the equation = 100.
Is there a way to solve this without brute force?
7
votes
2answers
379 views
Pensive Nonogram - Two-Colour Puzzle
Fourth two-colour puzzle in the 32nd issue of Mega Pixel Puzzles by Puzzler.. I’ve made some progress, but I am stuck. Can you help me find my next move in it? (The puzzle is below)
7
votes
1answer
253 views
The Newest Cycle
A wonderful new chess problem has appeared lately that is most wonderful. I am here to share it with the world today. But you must solve it in order know about it’s glory!
It’s White to move and ...
17
votes
3answers
3k views
Prime to Prime: Get all first 25 Prime Numbers using up to 4 Primes
The first 25 Prime Numbers are
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
Using up to 4 prime numbers and the following mathematical operations, get all the 25 primes.
...
10
votes
1answer
417 views
Twelve Labours - #12 Pluto Pups
This puzzle is part of the ‘Twelve Labours’ series, but can be solved independently. Previous instalments can be found here: Prologue | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11
It was ...
3
votes
1answer
159 views
Rotary phone with numbers and letters
I am going to organise a quest for teenagers.
I have a vintage phone like below:
I am looking for ideas how to use the rotary phone with
numbers 1,2, ..., 9, 0 and letters
A, B, C, F, H, I, K, L, M, ...
8
votes
1answer
688 views
12
votes
2answers
778 views
Hearts and Spades in a Row
From a deck of playing cards remove hearts ace to seven, and spades ace to seven. Now place them on a table in a row so that the number of cards between the two aces is 1, the number of cards ...
3
votes
2answers
319 views
What was Grandpa really doing?
"Guess what happened during my walk". Said Grandpa
"I saw gods in a ghetto"! He continued with a smile.
"What?" I said.
"Well, not really. But can you guess what I did?", Grandpa asked.
...
4
votes
1answer
99 views
You Tell Me What To Choose
I found this nice problem in A.C. White’s 1912 book “The Theory Of Pawn Promotion” the other day. Enjoy!
It’s White to move and checkmate Black in 5 moves, Don’t forget to explain the title!
...
2
votes
4answers
619 views
Grid Puzzle - Paint
A student was found making Graffiti in the teacher's office.
He was punished and was asked to repaint the wall of the room.
The teacher gave him a grid to show which part of the wall should be painted ...
10
votes
4answers
2k views
What's the most rewarding path?
Get from the top-left to the bottom-right using only right and down moves. Pick up as much gold as possible. There is only one maximum.
3
votes
2answers
205 views
Minesweeper puzzle - Too many twos
A Gobo is caught for leaving the school for the lnternet bar to play computer games without permission. He is asked to solve a problem.
Put 4 mines in a 3 by 5 minesweeper grid to fill ALL the other ...
8
votes
2answers
270 views
Hand tiling puzzle demonstrating Eisenstein triple $c^2 = a^2 -ab + b^2$
An Eisenstein triple is related to 60 degree triangles and a special case of the cosine law. But we need not worry about that except to note that a specific example of an Eisenstein triple is $7^2 = 5^...
10
votes
3answers
294 views
Four hand tiled squares demonstrating a Pythagorean Quadruple
Demonstrating the Pythagorean Quadruple
$6\times6 + 6\times6 + 7\times7 = 11\times11$
Using the pieces shown in the $11\times11$ square:
The objective:
Arrange the pink pieces (four enneominoes) ...
4
votes
0answers
170 views
The Rambling Monster
The Rambling Rook is back, but this time, they are a true monster!
It’s White to move and reach a winning position in 101 moves.
Gijs van Breukelen, Schakend Nederland, 1981, Special Honoring ...
17
votes
1answer
945 views
Son of the Revenge of the Riley Riddles in Reverse Strikes Again
Because why not, here's yet another bunch of these inverted riddles, where the solutions are what you'd usually use as the wordplay clues in a Riley Riddle. Here's how it goes:
You get three words.
...
6
votes
1answer
100 views
A Curve of Pursuit Yajilin
Following on from my previous Yajilin, I wanted to make a harder one for your entertainment and amusement, and hopefully to keep @Deusovi occupied for more than 20 minutes.
Rules (shamelessly ...
0
votes
1answer
71 views
TripTog's problem with his socks [closed]
Our friendly three-footed alien TripTog has two triplets of socks, which he keeps in a drawer in a room.
Each triplet of socks is labeled 1, 2 or 3, because TripTog is very meticulous about which ...
4
votes
1answer
132 views
“Short” And Sweet Math
In the following chess diagram, how many possible chess postions exist?
No looking at the solution!
Source: P1359129 & Andrew Jonathan Mestel,
Retros mailing list, 2/1/2019
6
votes
5answers
208 views
Chess Construction Challenge #3-The Inverse Babson
Another day, another task!
Today's challenge is to construct four positions, with White to move and win, such that:
In each position, White's move is to promote to a particular piece, for a position ...
7
votes
4answers
2k views
Smallest number containing the first 11 primes as sub-strings
113257 contains the first 6 primes as sub-strings when reading them from left to right:
2: 113257
3: 113257
5: 113257
7: 113257
11: 113257
13: 113257
What is the smallest number that contains ...
3
votes
2answers
180 views
Back in time, in my time, all the time
I present to you all a highly interesting problem that I came across awhile ago on Tim Krabbe’s site.
It’s White move and win, i.e. reach a winning positon, in 21 moves.
David Gurgenidze & ...
13
votes
1answer
876 views
Dear Fellow PSE Users,
This puzzle is dedicated to all of you!
Instructions
There are 8 anagram questions below.
In each question, you can rearrange the letters to find an answer, which is 2 English words that describe a ...
10
votes
2answers
676 views
The Google Earth Challenge: “A dangerous flower”
This puzzle is based on Where is it? - The Google Earth Challenge series started by Conifers
This puzzle will provide a screenshot in somewhere on Google Earth, please try your best to identify where ...
11
votes
2answers
226 views
Missing lattes and mutually mistrustful words
It's always amusing to watch two kids who don't trust each other swap baseball cards by exchanging them at exactly the same moment. Words can be equally mistrustful about trading their letters. ...
7
votes
2answers
331 views
Not Seven This Time - another Google Earth challenge
Where is this?
Please don't use Google reverse image search, but solve the puzzle using inspiration and deduction.
11
votes
1answer
296 views
Don't look back, crazy clown
Start with these two words
INSANE RETROSPECT
and see if you can get them to exchange places by transferring one letter at a time. With each ...
7
votes
1answer
151 views
Manually mixing words
Inspired by my struggles with this puzzle.
In that puzzle, I needed to mix two words, meaning blend them together without changing the order. For example, "ab" mixed with "cd" would give us 6 new ...
9
votes
1answer
495 views
Connect the wires without setting off the bomb
You just saw a planted time bomb! Just 5 minutes are remaining until it explodes and as you are in currently in a rural area (no bomb disposal squad) and you know how bombs usually work it is up to ...
4
votes
1answer
155 views
A Remote Location
Here be a simple problem
For the keen directmate eye
White to move and win
In seven moves, Black shall die
However, I remember now a relative
Long ago did he begin to live
About a two decades or ...
20
votes
1answer
726 views
The little bee buzzes around the flower garden
Watch the little bee buzz around the flower garden. Pay particular attention to how he picks up or drops off pollen (i.e., a single letter) at each flower.
Notice:
— The little bee visits each ...
8
votes
1answer
549 views
Winning the Lottery
Bob: I hear you won the lottery.
Alice: So I did!
Bob: What six numbers did you win it with?
Alice: Can't remember. All I recall is that they were all different, and none greater than 28.
Bob: ...
14
votes
2answers
973 views
The 7-numbers crossword
This crossword doesn't have any regular clues, however, all the words are made with the same 7 letters (each of them got a number). No automatic solvers are allowed.
CSV version:
...
7
votes
1answer
219 views
A Game of Sprouts
I have a partially played game of sprouts that I need help solving. The rules are simple (Kevin over at VSauce2 did a great job explaining it if you don't like reading, though the Yoda voice is a bit ...
2
votes
0answers
168 views
Around The World
It's White to move and checkmate Black in 36 moves. I have slightly changed the original stipulation. Feel free to explain the title if you want to!
*Oleg Pervakov and Karen Sumbatian, Shakmaty v ...
-1
votes
1answer
51 views
lightest ball among 8 balls by 2 tries using a balance scales [duplicate]
I have 8 balls and one of them is lighter than others. How could I find that ball by 2 tries? Also I have a balance scales.
3
votes
1answer
95 views
Alphametic puzzle, involving square and prime numbers [closed]
I have been trying puzzle solving recently and came across this problem.
Any hints on how to do this?
So far, I have found that N, R and F must be odd (as they are the last digit in a 5 digit prime ...
9
votes
3answers
428 views
So, what's to do?
It's White to move and draw the game. What must White do?
You must provide proof for your claim of what's to be done by any reasonable means. No looking up the solution please!
Nikita M. Plaksinm ...
4
votes
2answers
202 views
The Dropper, But With A Twist
Here's a piece-drop puzzle of my own.
In the below position, a White piece is to be dropped onto the board. This means that, before White can move, they must legally put a single piece on them board.
...
10
votes
1answer
462 views
100 Years of GCHQ - A quick afternoon puzzle!
I'm off to the Science Museum London tomorrow, to the Exhibition celebrating 100 years of GCHQ. As such, they sent me a little reminder email this afternoon.
On the bottom of the email was the ...
2
votes
1answer
165 views
That Ain't Right… #4
Here's a small head-scratcher for you all today.
In the above position, it is White to play and mate Black in four moves, assuming that Black plays their best moves.
However, there is a catch—there ...
8
votes
2answers
1k views
Dodgy Dies: The Puzzling Premiere
Inspired by the "Treasure Hunter Monolith" minigame from Danganronpa V3
Dodgy Dies Guide
Terminology
Block - a single die on the grid.
Cycle - a list of blocks
Value - the ...
