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Questions tagged [no-computers]

A puzzle designed to be solved without using calculators, online decoders or computer programming.

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7
votes
4answers
1k views

Comparing exponents - no computers!

Which is larger, $99^{100}$ or $100^{99}$? Which is larger, $999^{1000}$ or $1000^{999}$? Or more generally, for $n$ any natural number: which is larger, $n^{n+1}$ or $(n+1)^n$? Please do not use a ...
7
votes
3answers
957 views

A bad and boring riddle, and an easy alphametic

First comes the bad and boring riddle (the answer is to be written in all capital letters): Magnesium plus Gallium yields a joke. Next comes the easy alphametic: Solve the answer to the bad ...
7
votes
3answers
643 views

No spanish required

Each letter represents a digit, so what is Mucho and Poco (although who's to say?) ...
7
votes
2answers
735 views

Last contact in custody

You came so close. The job was going so well. You just never expected that the police would have a surveillance cat. That's what you get for trying to steal things in an age where people are ...
7
votes
3answers
385 views

A colorful wheel

Here's an interesting puzzle. This is called "Rudenko's Disk" (Brainwright) — finding information or solves for it online isn't all that challenging, which would largely ruin the fun here, so ...
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 ...
7
votes
2answers
844 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 ...
7
votes
4answers
660 views

Tricky Tricky!-Can you find the secret?

Here's a selfmate problem that just might be baffle you! Thus, I name it "Tricky Tricky!" It's White to move and selfmate themselves in 8 moves. Can you find the secret? As always, no computers ...
7
votes
3answers
211 views

Multiplicative alphametic: This is too hard

Every letter and every question mark stands for a digit in base-10 representation Different letters stand for different digits Question marks are placeholders and stand for arbitrary digits (that ...
7
votes
4answers
184 views

Fill in the boxes to get the right equation v2

My take on a recent puzzle. Place numbers into boxes to create a correct equation, using each number at least once: $$\Box-\Box+\Box\times\Box=\Box\:/\:\Box$$ This time the four decimal numbers are ...
7
votes
2answers
738 views

Password Cracking

You are trying to crack someone's password. You don't have any password cracking software, nor do you have time to get any. From sources unknown, you know that: A. The password is alphanumeric (...
7
votes
2answers
245 views

Listen to my Story…Let us find the Unique Invisible Pan Digital Pair

I was an avid reader of Popular Science magazine. In the last page or so, they usually had visual clues without words to make useful stuff. I always wanted to create a mathematical puzzle like that ...
7
votes
1answer
385 views

It is as easy as A B C, Figure out U V C from the given relationship

Given $ U, V, C $ are three distinct digits, figure them out from the following relation: $$ \overline{CCC} = \overline{UVUVUV} \div \left ( \overline{UV} \times \overline{UV} \right) $$
7
votes
2answers
480 views

Escape the cube 2 (Theseus and Minotaur variant)

Hello, here is a puzzle I created. I plan to post a few more in the near future. If you like it, google Cubiscape for more. Goal: You are the blue ball and have to get to the green square without ...
7
votes
2answers
333 views

How many dates are ambiguous across the Atlantic?

The Day/Month/Year date system commonly used in Britain (and much of Europe?) and the Month/Day/Year system commonly used in the US can lead to confusion when, for example, we write 9/3/2018 for the ...
7
votes
2answers
319 views

Arrange numbers to 3x3 square with concentric (Addition and Difference)

2 Similar questions: I. Difference Arrange numbers 1 to 8 to replace the letters so: A = abs (B – D) C = abs (B – E) F = abs (D – G) H = abs (E – G) To eliminate duplicates by rotation and ...
7
votes
1answer
969 views

Aiming for the 24

6 1 3 4 = ?? Using four basic math signs (+, -, *, /) and brackets, for instance: 6 * (1 + 3) - 4 = 20 6 * 1 * 3 + 4 = 22 6 + 13 + 4 = 23 (6 + 1)* 3 + 4 = 25 61 - 34 = 27 Try ...
7
votes
2answers
650 views

A very evil cipher

A very evil tyrant locks you in a very evil cellar in a very evil castle. Every day he brings you a bit of soup and a bit of bread with a message he says, "It's the code but you have to decipher it ...
7
votes
1answer
335 views

1 crossword and 2 connected alphametic (more clues)

Rules : Solve the Crossword. The words can be written backward (example zebra -> arbez) After finishing the crossword, solve the alphametics. The crossword is only uses 10 letters. Each letter ...
7
votes
2answers
310 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
322 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.
7
votes
1answer
150 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 ...
7
votes
2answers
263 views

A Criminal Conspiracy (Who Is Guilty #4)

[Appeal: I'm trying to figure out a fun puzzle formula. There are many out there ("Who owns the fish", sudoku, etc). I'm interested in feedback on whether this works or is interesting for people. ...
7
votes
1answer
373 views

Arrange numbers to the triangles, so the sums are equal to S

Rules: Arrange numbers from 1 to 11, and each number can appear max twice. The numbers are arranged, so that any 3 numbers which forming an up-triangle sum to the desired number (S). A equal sign ...
7
votes
1answer
674 views

A Game with Strings and Coins

Alice and Bob play a game using the following arrangement of coins, which are joined by strings and hanging from the ceiling: $\qquad\qquad\qquad\qquad\quad$ The two alternate turns, with Alice ...
7
votes
2answers
183 views

Puzzling Knight has a Message for all- Especially Newcomers

Of all the more than a Trillion messages he can deliver, he has especially selected this message for all. Follow his(normal chess moves for the Knight) path to get the message. His journey starts ...
7
votes
1answer
2k views

Find the missing numbers in the magic square

The following is a magic square: each row, column and diagonal add to 34, all of the numbers 1 to 16 appear exactly once. Find the missing numbers.
7
votes
1answer
310 views

Escape the cube puzzle

Hello, here is a puzzle I created. I plan to post a few more in the near future. If you like it, google Cubiscape for more. Goal: You are the blue ball and have to get to the green square without ...
7
votes
1answer
208 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 ...
7
votes
1answer
533 views

Don't bully your little sister at chess

This puzzle was inspired by @RewanDemontay's puzzle De-zephyr The Solution!. Rewan kindly granted me permission for making this puzzle and citing his as my source of inspiration. I thought of naming ...
7
votes
2answers
255 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! ...
7
votes
1answer
192 views

Stars of the Celestial Bagua

Check this out: Okay, it might be more impressive if I show you what is moving along the arrows: At every vertex in a long word. Flowing in to every vertex are two short words ("inputs"). ...
7
votes
1answer
175 views

Unsolving a Rubik's Cube

A few days ago I picked up a solved Rubik's Cube that I had abandoned due to forgetting how to solve it, and started turning the faces to make nice patterns. A few minutes later, I'd made one - each ...
7
votes
1answer
200 views

Subtraction square dance alphametic

Every letter stands for a digit in base-10 representation, different letters stand for different digits, and leading digits are always non-zero. ...
6
votes
4answers
3k views

Are perfect cubes possible?

Based on this. Can you find 4 distinct integers a, b, c, and d such that a+b, b+c, c+d, a+b+c, b+c+d and a+b+c+d are all perfect cubes? If not, prove it.
6
votes
8answers
1k views

A word exercise : Same consonants and five vowels [duplicate]

Can you think of 5 different 5-letter words which use the same 4 consonants and each word includes one separate vowel? You must use all 5 vowels. In all 5 words, the 4 consonants and one vowel must ...
6
votes
5answers
1k views

Long digital sequence. 16xxxxxxxxxxxxx61

Find the digital key and very simple method to unlock the long digital sequence 16xxxxxx61 Additional clues: Eeryday one clue will be given till problem is solved Day 1: Bounty Day 2: My code is ...
6
votes
2answers
2k views

100 Fruits for 100 Dollars a more challenging version

This is a more challenging version of the reported puzzle " How will you get 100 fruits in Rs. 100? " Bob buys 4 different fruits for exactly 100 dollars Jackfruits cost 15 dollars each ...
6
votes
3answers
954 views

Baseball games alphametic

Every letter a decimal digit, different letters for different digits: BASE + BALL -------- GAMES Which digit does each letter represent?
6
votes
3answers
545 views

My First Math Riddle

Okay, so I write a lot of Riley and story riddles; however, I've noticed that I like the mathematical riddles too! I decided to write one, and I hope you all enjoy it. A few rules: No rotation. No ...
6
votes
4answers
450 views

Backwards pawns

Part One: Reach the above position from the starting position Part Two: Find the fastest way to get to this position. Answering part one will get you an upvote, answering part two gets the ...
6
votes
3answers
396 views

Lucky Lottery Tickets

Six-digit lottery ticket numbers are considered lucky if the sum of the first three numbers is equal to the last three. Eg. 123204, 871529... Prove that all possible lucky numbers added together is ...
6
votes
2answers
213 views

Square-root of CAREER alphametic

Every letter stands for a digit in base-10 representation, different letters stand for different digits, and leading digits are always non-zero. $\sqrt{CAREER} \,\, = \,\, RUT $ Which digit does ...
6
votes
1answer
506 views

Lights in the theatre

A play of Romeo and Juliet is being held in the theatre tonight, hundred of people have been waiting this moment for months. Many people are currently working hard in the theatre to adjust the final ...
6
votes
5answers
197 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 ...
6
votes
2answers
361 views

Go Get the Six Six-Pack

And fill with right Mathematical operands and enjoy. Six Relations shown in the pictures are missing the right operands. You can only use plus, minus, multiplication, division signs in between the ...
6
votes
1answer
1k 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 ...
6
votes
4answers
359 views

How do you transport 42 cars?

You're a soldier in the dictator's army. The dictator is very impressed with your incredible abilities. He asks you this question: There are 42 cars in this parking lot over there. How do you ...
6
votes
3answers
456 views

Calculator Bomb

So, I need your help. I got home after a long day and found a calculator roughly taped to my door. However, there was something much more disturbing attached to that calculator. It was some kind of ...
6
votes
1answer
164 views

Alfred E. Neuman alphametic

Every letter and every question mark stands for a digit in base-9 representation. Different letters stand for different digits. Leading digits are always non-zero. An alphametic for the lovers of ...