Questions tagged [no-computers]

A puzzle designed to be solved without using calculators, online decoders or computer programming. You're still allowed to use a computer to post the solution; Stack Exchange doesn't support smoke signals yet.

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13
votes
1answer
262 views

Follow the path of relation through the grid #1

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
7
votes
1answer
179 views

Follow the path of relation through the grid #2

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
6
votes
1answer
156 views

Follow the path of relation through the grid #3

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
20
votes
5answers
800 views

Square Spin #1: Sun and Moon

Defining Square Spin Lets play a game! The aim of this game is to transform one image into another using the least amount of moves possible. Here is what a move consists of: ...
14
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2answers
336 views

Barrel - Part 5

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Title based on this xkcd. This is a continuation of Barrel - Part 1, Barrel - Part 2, Barrel - Part 3, and Barrel - Part 4, but this ...
13
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3answers
831 views

Some Stratospherically Strenuous Sudoku

These three sudoku are particularly irksome, can you logically deduce the solutions to all (or any!) ...and provide your reasoning? They are all proper sudoku - each has a unique solution. They can, ...
18
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2answers
836 views

Color Logic - Find the rule

Find the rule specified in the image below. (Where I got it)
37
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1answer
2k views

Riley Riddles in Reverse

In the all-famous Riley riddles, you have to guess one word from clues about its prefix, infix and suffix. Here, instead, You get three words. You must find one solution word that you can attach.....
22
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7answers
4k views

What number is that ? Asks Grandpa

"So here is a number between 1 and 60" Says Grandpa "If you take its WORD anagram and subtract this number you will get Anagram of the number - number > 5 What is that number"? "So it is the ...
12
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2answers
1k views

Alphabetical Sudoku

Who loves fish? Okay that might sound a bit weird but don't worry, I am still sane. Maybe. To answer the question you must complete the Sudoku below. A word will appear in the highlighted box which ...
15
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3answers
369 views

Some-what-not-with-standing word connections

What words can fill the boxes?   Each pair of linked words forms an uncapitalized unhyphenated word when joined end-to-start according to their left-to-right or top-to-bottom order in the link. ...
7
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2answers
329 views

Desert Wanderings bring…Ciphers? Part 2

Part 1 can be found here Part 3 can be found here As you utter your answer, along with its reasoning of course, the Sphinx clearly looks disappointed. You are unfortunately… Correct. Clearly I made ...
7
votes
2answers
314 views

Square Spin #2: Climb the Mountain!

Square Spin History: #1>#2 New Rules This puzzle introduces two new square types: Unmovable squares (Un) Replaceable squares (Re) Plus the concept of ambiguity! Ambiguity of squares Certain ...
5
votes
2answers
168 views

Follow the path of relation through the grid #5

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
16
votes
9answers
4k views

Solitaire Chess

A friend of mine got me Solitaire Chess for Christmas years ago. I set up the board below. Is it possible to solve it? If so, what is the solution? (No programs allowed- Use only your brain.) Rules: ...
14
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9answers
4k views

Perfect Squares!

A question was asked in a mental ability test yesterday. Write four distinct numbers with these properties: 1. Sum of each pair is a perfect square. 2. Sum of all four is also a perfect ...
10
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2answers
7k views

Find the 4-digit code!

An agent has created a 4 digit code from the result of a maths equation involving all the digits 1-9. We know where the number 3 appears in the multiplication, but not any of the other 8 digits. <...
18
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7answers
2k views

Fully-Firstable Anagram Sets

Okay, first let's define some terminology: Anagram - Oh come on, how are you on Puzzling.SE if you don't know this one? Anagram Set - a list of words that are all anagrams of eachother, e.g.: ACTS ...
14
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3answers
1k views

If 6 was 9, or 100 was 64, or M was N

         Now if a 6,          Turned out to be 9,          I don’&...
6
votes
1answer
2k views

Encoding Morse Code

The letters of a message are converted to Morse code, with a space between each pair of letters and two spaces between each pair of words. Each pair of elements (for example dot-space, dash-dash, and ...
19
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2answers
1k views

Self-intro to mo-Roman numerals

Here come mo -Roman numerals — just like Roman numerals, only mo’ so.   (Explained as we go.)   What number can spell itself in two different ways ...
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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. + ...
13
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3answers
1k views

Crossword gone overboard

This puzzle is part 24 of Gladys' journey across the globe. Each part can be solved independently. Nevertheless, if you are new to the series, feel free to start at the beginning: Introducing Gladys. ...
10
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2answers
316 views

How to fill a honeymoon

        How can a honeybee visit all cells exactly once in this crescent shaped honeycomb, beginning at the bottom tip and ending at the top? The starting cell, at ...
7
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2answers
919 views

Triangle with incircle [closed]

This question is from the German mathematics competition Känguru der Mathematik. In this competition students have to solve 30 mathematical tasks like this in 90 minutes without calculator. Actually ...
10
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2answers
3k views

How many Strobogrammatic numbers are there from 0 to 99999

0,1,2,5,8,11,69,96 are Strobogrammatic numbers. We call a Strobogrammatic numbers if: When it is typed on a calculator, and the calculator is spun 180 degrees, the number visually looks the ...
9
votes
1answer
282 views

Simple Homeworlds puzzle

On this site, we have numerous chess puzzles. however, we do not seem to have any Homeworlds puzzles, the game of space kings (yes this can be tagged outer space thank you very much.) Hence, here is ...
9
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2answers
278 views

Word connection squares!

This puzzle is in the spirit of Word connections, but is a more elaborate version of the same idea. In each puzzle, you have a square of seven words of the following form: ...
5
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1answer
87 views

Follow the path of relation through the grid #6

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
4
votes
4answers
389 views

Word connections

I am trying a new kind of puzzle so feel free to leave constructive comments and opinions! Thank you! The objective of this puzzle is to connect 2 words by using a chain of words that connects each ...
3
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1answer
98 views

Follow the path of relation through the grid #4

There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
2
votes
2answers
104 views

Tiling rectangles with Hexomino plus rectangle #2

Inspired by Polyomino T hexomino and rectangle packing into rectangle See also series Tiling rectangles with F pentomino plus rectangles and Tiling rectangles with Hexomino plus rectangle #1 ...
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2answers
169 views

Tiling rectangles with Heptomino plus rectangle #7

Inspired by Polyomino T hexomino and rectangle packing into rectangle See also series Tiling rectangles with F pentomino plus rectangles and Tiling rectangles with Hexomino plus rectangle #1 ...
57
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2answers
3k views

Sudoku like you've never seen it before

I've spent this week trying to create a difficult logic puzzle which is a combination of two Sudoku varaints, 'Samuari Sudokus' and 'Pseudokus', and this combo is unlike anything you can find online. ...
30
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1answer
2k views

A Secret Job . . . but what is it?

Mr. Peters, a freelance muscle-for-hire sort of fellow, had been manning his desk for days now waiting for something to do when at last the phone rang. A job! The nerdy sounding person on the other ...
50
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1answer
2k views

re-re-reCAPTCHA

Last Friday, I was feeling a bit sad because I hadn't earned much rep recently, so I decided to try this awesome sock puppet thing everyone's been raving about. I logged out of my normal Puzzling ...
47
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2answers
3k views

Can you stop the rambling rook?

This is a chess puzzle someone showed me a long time ago. If you already know this puzzle please give the others a chance to solve it first. This puzzle was originally created by Otto Gallischek and ...
43
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2answers
2k views

A simple nonogram

Solve the nonogram.                   (Click for a larger version.)
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3answers
5k views

First digit of 3^2020

Inspired by The last digit for 3^(2019) Can you find the first digit of $3^{2020}$ without a computer?
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5answers
2k views

Superhero words!

Quietly walking among us are words which are actually superheroes in disguise! Just as Diana Prince spins around to become Wonder Woman, some seemingly ordinary words can spin around to reveal their ...
51
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2answers
3k views

A 16 Clue Sudoku Puzzle (but the kings can't be in check)

An entry in the 19th fortnightly challenge... Above is a 9x9 "chess" board with some pieces already laid out, your goal is to fill the board completely, following standard Sudoku rules (i.e. every ...
29
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3answers
3k views

Uh oh, the propeller fell off

I was rummaging through a trunk in the attic when I found this vintage game. It is some sort of pinwheel or propeller mounted on a board. The propeller has a cryptic series of letters painted on it, ...
16
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1answer
579 views

Riley Riddles in Reverse, batch 2

"post some more sometime :)" -- user @Dragonrage in the comments of Riley Riddles in Reverse Here's another batch of "inverted" Riley riddles. These still work exactly like the ones before: You ...
43
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4answers
3k views

Five Slitherlinks

Solve five Slitherlinks, each with a unique solution. Please say a word regarding (or show an image depicting) each solution method.
31
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1answer
2k views

Computation without a computer

In the number $(1+\sqrt{3})^{2015}$, what is the 224th digit after the decimal point? You may NOT use a calculator, computer, or any electronic aid to answer this question. Only pen(cil), paper, and ...
17
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2answers
978 views

Sudoku in the third dimension (3D Sudoku)

People seemed to enjoy my last Sudoku variant puzzle - Samurai Pseudoku, so I spent this week making another! This one is going to require using logic you've never used before... The last one was a ...
17
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1answer
1k views

The Lord of the Puzzles

In 1904 (at the age of 12) J.R.R. Tolkien sent a "puzzle letter" (pictured below) to a family friend; Father Francis Morgan. What does it say? Obviously it would be trivially simple to google the ...
8
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1answer
373 views

Whose birthday is it?

A group of people have gathered for a birthday celebration. Their ages are related as follows: The product of the 1st person's and the 2nd person's ages is $311\frac{2}{3}$ plus the 3rd person's age. ...
30
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2answers
2k views

Parallelisation

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Puzzlers, I am presenting a set of six duo-grids! Of course, I need to tell you how they work - you are given a grid. Looking at it,...
20
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1answer
1k views

Farmer needs to get his word across the river

In the spirit of the classic river-crossing puzzles: ...