# 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.

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### Elegant solution to this digit puzzle

Puzzle The letters $a, b, c, d, e$ and $f$ represent single digits and each letter represents a different digit. They satisfy the following equations:  a+b=d, \quad b+c=e \quad \text { and } \quad d+...
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### No Computer Allowed (Beware the Eater)

The answer is a relevant single word. No computer or digital calculator allowed. Beware the eater of red herring, if you happen to spot it. 6 - 5 + 4 + 7 = ? 7 + 8 + 8 - (7-5) - (7-1) = ? 6 - 5 + 7 + ...
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### A wordsearch for today

Sixteen 4-letter words have been concealed in the grid below, as well as one word that is much larger. Can you find all seventeen words? Text version of the wordsearch (for copy-paste purposes): <...
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### A massive synonym

Please explain how to assemble the puzzle. Yes, one is missing, but you can follow the >. No computers. Hint: Hint 2: Hint 3: Text version: ...
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### An overconfident grandmaster

Suppose you are playing a grandmaster with the White pieces and you are on the verge of losing the game. The overconfident grandmaster offers you a bet: You will make two consecutive moves with White ...
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### Using Prime numbers to get 100 and 1000

Using the digits 1 to 9 exactly once create a set of one or two digit prime numbers. Use those prime numbers and the math operations + - / * and parantheses to get 100. Then use those exact same ...
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### It is all in the past

Presented here are questions related to past tense words I researched and googled that resulted in this designed and developed puzzle. Got it? Which past tense word (PTW) is also a past tense word ...
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### Adding consonants to create an antonym

This is an emotional word with 2 vowels Starting with it create two words by adding 2 different consonants. The two new words are antonyms of each other. See below. What is that word? No programming ...
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### Five words, Five vowels, Five last names

These five words are from the Collins English Dictionary. Are also last names, And have one vowel difference in exact same location and same consonants in exact same locations. Example : Last Lest ...
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### A Complicated Exercise In Addition

Another day, another walk down to the cafe. I was waiting in line for my coffee, wondering what the barista could do this time to make my name look whack. But as I waddled in line, a curious site ...
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### Can you stop the falling piano with 23 nets?

MIT's Baker House has a tradition of dropping an irrepairable piano six floors every Drop Day, the last day one can drop a class without penalty (the 2022 date is 19 April). This year, in order to ...
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### Binary Sudoku Puzzle

The rules of Binary Sudoku are quite simple. It is very similar to regular Sudoku, except here we try to fill a 9x9 board with only black and white tiles following the below rules: Every row, column, ...
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### Permutations of first 10 natural numbers such that all the prefix sums are distinct

I posted this question on Math SE as well. Did not receive any help. This is a question that I was asked in a Quant Interview. I would like you all to have a crack at this. I could not find a problem ...
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### How many coins did Raj get?

I found a bunch of coins: Quarters (25 cents), Dimes(10 cents) and Nickels(5 cents). The combined amount was a whole two digit number of dollars: that is, no fractional amount. I divided the coins ...
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### When is my birthday?

Who am I? When is my birthday?
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### Fill in the blanks with numbers

A simpler version of this puzzle was by @Sid on PSE Fill in the blanks with the number in words Here is a bit challenging version Fill in the blanks with numbers (in words) for the following: This ...
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### Thirteen Diagonals of a Nonagon

A regular nonagon has 27 diagonals, and these diagonals intersect in the interior of the nonagon at 126 distinct points. Show that it is possible to select 13 diagonals of a regular nonagon such that ...
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### PSE Advent Calendar 2021 (Day 20): Candy Cane Sudoku

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > So I was ...
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### Genies' chess on a 10×10 board

The work of Hearth Taxel revealed some other results related to genies' chess. For example, there is an arrangement $A$ of pawns on a 10×10 board such that no 3×3 submatrix is empty and $A$ is ...
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### PSE Advent Calendar 2021 (Day 4): Decorating with Ingrid Deduction

This puzzle is part of the Puzzling StackExchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation. < Previous Door Next Door > "...
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### Three missing digits in 42 factorial

When calculating $42!=42\cdot41\cdot...\cdot2\cdot1$ the result is $42! = 140500611775287989854x14260624y511569936384z00000000$ However three digits have been replaced by $x$, $y$, and $z$. Can you ...
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### Copy that solution

This copy machine program prints the solution to a well-known puzzle.  Explanation of the syntax will follow. What solution will be printed for which well-known puzzle?  EXECUTION CODE .--> ...
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### A Grand Game (Find two words)

Find 2 relevant (but not strictly related) words using a logical method. One ends in 'R', the other in 'E'. The method should be one which leads to the exact and specific letters for each word (no ...
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### Some blissfully ignorant math?

I was playing around with the code for my game the other day in an effort to create some unique effects. One thing I created was what I called an "ignorant assignment" in which I applied ...
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### Knight tour on a racetrack

Help the chess knight complete four clockwise laps on this racetrack, so that he lands on every square and never lands on the same square twice! The final square the knight lands on will be the same ...
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### Seven 2s with seven math operations

Linked to A four digit number using exact same 4 digits A number with same repeated digits is called a Repdigit or Monodigit number https://en.wikipedia.org/wiki/Repdigit Can you write an equation for ...
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### Hero Worms and The Minotaur

And so, Wormeus had a great time, eating every apple in sight, surviving several close calls with the Pink Lady Stickotaurs, respawning after the occasional horribly squishy death, exploring different ...
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### Going off on multiple tangents

Given two disjoint circles of diameters D1 and D2 draw all shared tangents. Find the intersection points of all pairs of tangents. Discard those collinear with the two circle centre points. Of the ...
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### Triangles to diamonds

Given a triangle ABC with sides a=|BC|,b=|CA|,c=|AB| a diamond is circumscribed around the triangle's incircle. The diamond and the triangle share the corner C along with (part of) sides a and b. ...
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### Can you pick up an extra shift?

I was going through some old documents the other day and found some instructions for a one way cipher: Given a word w, iterate over its characters. For each character c, determine if its zero based ...
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### A four digit number using exact same 4 digits

ABCD is a 4 digit number where A,B,C and D are 4 distinctly separate digits between 1 and 9. Using any of the following math operations and the digits A,B,C and D exactly once get the number ABCD. ...
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### Wormeus and the Multiple Stickotaurs (Part 2)

This is the sixth puzzle in the Wormeus series and the second puzzle involving multiple Stickotaurs and wormhole puns. Wormhole-pairs are indicated with light green lines (note that this was ...
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