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:
...
- 11.8k
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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 ...
- 841
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2
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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 ...
- 38.8k
6
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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 ...
- 38.8k
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2
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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 ...
- 38.8k
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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, ...
- 71
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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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5
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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 ...
- 38.8k
2
votes
1
answer
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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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1
answer
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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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2
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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 ...
- 11.5k
4
votes
1
answer
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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
.--> ...
- 21.3k
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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 ...
- 11.8k
3
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1
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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 ...
- 10.5k
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1
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Fractions and Fractional Numbers
Using fractions and fractional numbers of the digits $1$ to $10$ and only the mathematical operations of addition, subtraction, multiplication, and division, including parenthesis (e.g. $1 + 2 - (3 * ...
- 38.8k
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2
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Consecutive integers which have digital sums that are not relatively prime
What are ten smallest natural numbers n, such that n and n+1 have digital sums which are not relatively prime?
- 14.3k
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1
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What number comes next in this evenly doubled sequence?
I've been playing around with sequences lately and found a pretty evenly doubled sequence of single digit numbers:
1, 12, 30, 64, 65, 156, 175, 368, 369, 371, 752, 753, 1524, 1525, 3060, 3073, 6168, ...
- 10.5k
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1
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An oddly formed sequence?
I've been playing around with sequences lately and came across one that was rather, odd.
$101$, $123$, $147$, $189$, $191$, $213$, $217$, $279$, $...$
Hints
Let $N_i = 101$...
Can you determine the ...
- 10.5k
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1
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A number like waldo?
What is the smallest whole number that when its individual digits are summed, produces a number 4 digits long? For example, the number $5357$ is no where close since $5 + 3 + 5 + 7 = 20$.
Note: I'm ...
- 10.5k
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This Unusual Year
Our current year, 2021, has the unusual property that the digital sum (the sum of the digits) of its square is precisely equal to its digital sum squared. Indeed: 2021^2 = 4,084,441, whose digital sum ...
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Powerful Octagon
Place different integers on the vertices of an octagon so that the sum of the integers in any two vertices joined by one of its edges is a power of 2. Do so in such a way that the largest integer used ...
- 14.3k
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The Thieves and the Gold Bars II: Greed and Distrust
Two thieves, Bo and Jo, steal 7 gold bars and are driving away when their car is wrecked in an accident. They-and the loot- is intact.
They are at Point A at 8 PM and must go to Point B which is 1 ...
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Tiling three pears with three-pair hexominos
The 21 hexominos below are all those that can be made by joining three dominos together (i.e. they have a perfect matching with respect to the graph of their squares) and are not rectangles. The ...
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White to play and mate in 3 - adapted from real game
This is adapted from a real game between GMs where white played the King's Gambit. I changed the position slightly (moved one piece) because there were actually two mates available, with one more ...
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Puzzling rectangles [closed]
Can you find two unequal rectangles whose areas add to $5\sqrt5$?
No computer solutions please.
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Heteropalindromes in a Word Square
Say hello to a not-so-simple, 4x4 word square:
This little monstrosity has two rules; to define the first rule, have you ever heard of a heteropalindrome?
Strings of letters that form words when ...
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How do I ring my friend's doorbell?
My friend, a curmudgeon who dislikes visitors, recently installed a puzzle-doorbell. It consists of ten push buttons in a row, labelled from left to right:
...
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The Thieves and the Gold Bars
Two thieves (Rod and Lia) carry out a big heist and steal 16 gold bars. They get away in their car when they run into a bad accident and the car is completely wrecked. Luckily they survive with their ...
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Most points on a circle
What is the most number of integer lattice points that lie on the circumference of a single circle whose radius is 80 or less? Please no computer computations.
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Life, uh, Finds a Way
[Rated PG-13 for language}
I saw someone wearing a "Life happens" t-shirt, which is a fine enough sentiment, but not the most common turn of phrase. It made me wonder...
How fast can you ...
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Sum of the first 86 square roots
Without using a calculator or a computer, can you compute the sum of square roots of the first 86 natural numbers, rounded to the nearest integer? In other words, we are looking for $\sqrt{1} + \sqrt{...
- 25.1k
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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 ...
- 31.3k
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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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When was Ensquare born?
Professor Matlogic posed this question to his smartest math student:
"Famous mathematician Ensquare was born on this day, this month and this year AD at this time (hour and minutes) pm. True to ...
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