Questions tagged [no-computers]

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

421 questions
265 views

A magical operation #2

Quick reminder of what is a magical operation A magical operation on a particular number (not ending by 0) is the addition of this number with his symetrical number. For example the magical operation ...
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Let's go back in time!

Okay, so below are a handful of ciphers. They're pretty easy to identify, ranging from simple substitution to complicated binary. Some may have the keyword given others you have to solve. Now you're ...
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A magical operation

A magical operation on a particular number (not ending by 0) is the addition of this number with his symetrical number. For example the magical operation for 2018 would be 2018 + 8102 = 10120. Let ...
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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.
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Make numbers 0 - 11 using the digits 2, 0, 1, 8; BUT

... seriously, this is definitely NOT that "kind of puzzle"! ;) So let me create this puzzle to freshen you up! It is inspired by a meta question: Yet another 2018 puzzle. Put the digits 2, 0, 1, ...
227 views

Challenging 15 rectangle tiling problem

This will test you, a computer will definitely help. Just one set of $1:2$ aspect ratio rectangles this time, but $15$ of them. Short side only is listed. The challenge is to arrange them into a ...
321 views

How many 5+ letter words can you find?

NYT does a word hive in every Sunday edition, and I quite enjoy it, so I decided to make my own, using the same rules. Check it out: If you're unfamiliar, here are the rules. You may only use the ...
165 views

Slightly bigger 1:2 hand tiling, getting a little harder

Pretty sure an expert hand tiler would be able to find this. Please post a spoiler only if you hand tile it... Tile a $60\times60$ square with $1:2$ rectangles of sizes ...
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Trickier hand tiling

This should be a little trickier. Using $20$ rectangles of aspect ratio $1:2$, make two squares. Use sizes 2,3,7,12,16 in both squares. And split this list among ...
188 views

Two similar hand tiling puzzles

Make a square from each of these lists of aspect ratio $1:2$ rectangles 1, 4, 5, 6, 7, 9, 11, 12, 13, 14, 15, 17 ...
113 views

Dissect a square into 1:2 non-congruent integer-sided rectangles

(Similar to the recent 3:1 and my 3:2 rectangle question) Tile a square completely with rectangles which have aspect ratio 1:2, integral side lengths and all different sizes. In other words selected ...
3k views

The Ultimate Typo

Here are four sentences that I made up. But I accidentally shuffled the characters in every column! Can you figure out what the original sentences were? ...
377 views

So many names in this place

The spelled name of this one word place is kind of interesting It has within its name: Three first names One last name One name of a country One name of a Province/State/Territory One ...
120 views

Hand tiling puzzle 2

Here's another set of polyominoes (sizes 4,5,6,7,8,9,10) that you can print and cut out. As before, the two smallest (same pieces as previous version) make a 3x3. The rest of the pieces are different. ...
199 views

Hand tiling puzzle

Here's a set of polyominoes (sizes 4,5,6,7,8,9,10) that you can print and cut out. You can use the two smallest to make a 3x3. Nice easy one to get you started. Add a piece to make a 3x5. Add another ...
2k views

Optimal Money-Saving on the NYC Metro

You are on vacation in New York City. You didn't bring your car, and it's currently around $-50^\circ C$, so it's probably a good idea to take the NYC metro subway to move around. You need a metro ...
173 views

How many dimensions?

You have $n+1$ points in $n$-dimensional Euclidean space, such that the mutual distance between each pair of points is the same. Now imagine an $n$-dimensional generalization of a sphere, such that ...
599 views

What is the probability that all the bullets will be destroyed?

A gun shots bullets with different speed each second. The bullets form a straight line. The bullets keep their speed (not getting slower or faster). But if 2 of the bullets collide, 2 of them are ...
7k views

A word pronounced like letters

Can you give me a word that when pronounced, sounds exactly like pronouncing some of the letters of the alphabet. For example The word TEEPEE sounds exactly like the letters T and P so TP, just as ...
162 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 ...
5k views

Another Easy Mate in 1

Standard chess rules apply, the board is not rotated (i.e. white pawns move upwards), no lateral thinking is needed. Simply find the one move for white which mates the black king. This puzzle was ...
651 views

Word list: 2 consonants 2 vowels

Original 4 letter word Two consonants Two Vowels All next words use the exact same 2 consonants and exact same 2 vowels. Order not important Next word 5 letters Same 2 consonants same 2 vowels ...
288 views

Multibranched tree

The Furca Fractalis tree grows in a very special way. Starting with the trunk there are three possibilities to continue growing: It can split in two branches. It can grow one branch and one leaf. ...
425 views

An incomplete set of numbers

Here's a fun math thing: Imagine building a set of non-negative integers, starting with zero. As you check increasing numbers, you add it to the set if doing so does NOT create a subset of three ...
2k views

How many coins did Mrs. Jones have?

Mrs. Jones is celebrating her 43rd (Prime number) birthday. Over the years she has collected gold coins. The number of coins is a Prime number less than 100. She decides to give all the coins to her ...
710 views

Anagram fills all the blanks

Continuing with the theme " Same word fills all the blanks" here is a riddle where the anagrams of ONE WORD fill all the blanks. One concession: Apostrophe allowed. NO using Anagram Solver or any ...
159 views

Polygon neighbors

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 ...
5k views

Six pyramids in a cube

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 ...
388 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 ...
791 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 ...
199 views

Irrationality in the balance

Sensibilly -T ™ scales were out of stock, so Gramazon filled the order with a lousy Lopside® from Irreturnable Irrationals International, Inc.73205080...  How ...
404 views

Gone ortho-flogging

Well played, Scratchy, you just took 8 shots on Hole 9 of Puzzlington Municipal Ortho-flog Course! As presented As flogged (solved) by you --------------...
697 views

The distance between David and Eric

Alice and Bob are looking at each other, both turn $10$ degrees and now they both can directly see Claire. If they continue turning in their same directions before, Alice will directly able to see ...
1k views

What are these numbers?

A simple (I think) alphametic puzzle $\small{MADMEN = (M+A+D+M+E+N)^{((M+E+N) - (M+A+D))}}$ M,A,D,E,N are different (no repeats) positive integers between 0 and 9 and of course the 2 Ms are the ...
321 views

Sum of three six digit numbers

This puzzle is a variation of a 3 digit addition puzzle I saw recently. A , B , and C are positive integers between 0 and 9. A,B and C are different integers Six digit numbers formed using A,B and ...
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Three words with three animals

Can you give me at least 3 ( I found 4 so far) Five Letter words with at least 3 animal names spelled in them? No anagrams (rearranging letters). The 3 animal names must be in ONE WORD. Find 3 ...
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Tom's mysterious alphanumeric character

Tom: I drew a mysterious alphanumeric character and showed it to Harry. Dick: Harry, was it a letter or a number? Harry: I'm not sure! Dick: Assuming it was a letter, was it uppercase or ...
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What's the missing pattern? 3x3 grid, dot pattern

What is the missing piece to this pattern? Got it as a quiz at work - no one here knows what it is!
537 views

The SUM 50 Game

Attached Grid (Total 5 x 5) has a black box grid (3 x 3) inside it. The Black box grid needs to be filled out with numbers 1 thru 9 using all numbers once. The Outer Red box squares (Total 16 ) need ...
339 views

Which letter completes this puzzle?

As shown in picture below, which letter completes the puzzle ? It bogging me for few days already ...
242 views

Can this be undone to make a knotless loop?

Can this be undone to make a knotless loop?
427 views

My Friend, 4 kids and gold and silver coins

The other day I met an old college friend in a coffee shop. We both were students in the Math department of that college. Here was our conversation (after the small talk) We are meeting first time ...
663 views

solve this 8-puzzle

This quiz is about the 8-puzzle. It is a board with 9 fields. There are 8 tiles with numbers from one to eight. One field is empty. You can slide numbers around the board: But only numbers next to the ...
6k views

Crack the 5 digits code

I created this "crack the code" puzzle. I hope the members here like it.
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,...
625 views

Move 2 or 3 spaces in this 5 by 5 grid

You have a 5 by 5 Board as shown. You start from the S (Center) position. You can: 1 Move TWO or THREE spaces only 2 You can move Vertically or Horizontally or Diagonally but only in a straight ...
562 views

Beating at Eating, a logic-grid puzzle for literal logicians

\$\begin{array}{r|lll} &\text{Name}&\text{Surname}&\text{Dessert}\\ 1&\text{Agatha}&\text{Greed}&\text{cream puffs}\\ 2&\text{Bugsy}&\text{Forager}&\text{trifle}\\ 3&...
650 views

How to play Japanese mahjong part 1: Forming hands

Have you ever wanted to learn mahjong but thought the game was too complex to get started? Well this puzzle will help you learn the basics of forming hands! So come on, what are you waiting for? ...