# 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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### Too early in the morning to have SODA?

Each letter shown represent distinct digit...can vary from zero to nine. $COCA$, $COLA$, $SODA$ are three concatenated numbers. Figure these out from the following relation: $COCA + COLA = SODA$
3answers
633 views

### Tiling a rectangle with just the Y pentomino

Inspired by this question series, which was inspired by this question. They give rise to beautiful pictures (at least in the eye of the beholder mathematician) and some nice generalizable solutions. ...
1answer
541 views

### This word with a lot of past tenses

This interesting word is full of past Starts with a past tense verb. Add a letter at the end and you have a different past tense verb. Then add more letters at the end and you get yet ...
2answers
280 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: ...
2answers
251 views

### Square made up with polyominoes

A 3 x 6 rectangle has 2 holes in it as shown. Can you cut it into 3 polyominoes with different areas so that they can form a square? The pieces can’t be flipped when they form the square and two ...
3answers
462 views

### So, what's to do?

It's White to move and draw the game. What must White do? You must provide proof for your claim of what's to be done by any reasonable means. No looking up the solution please! Nikita M. Plaksinm ...
1answer
364 views

### Mini 8 queens puzzle

On a 5x5 chessboard, place 5 black queens and 3 whites queens so that no queens are attacking those who are of different color. Furthermore, the numbers indicate how many queens are attacking the ...
1answer
481 views

### Twelve Labours - #12 Pluto Pups

This puzzle is part of the ‘Twelve Labours’ series, but can be solved independently. Previous instalments can be found here: Prologue | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 It was ...
1answer
619 views

### Narcissistic cube asks who are we?

I am a five digit narcissistic cube who likes to display my root right upfront. I also have hidden it in the back of my four digit cube brother. Who are we?
1answer
354 views

### Like totally amazing interchangeable sister outfits II: The Revenge

The sisters have learned a few lessons from their recent debut. They are now ruthlessly efficient outfit-swapping machines. (You know, sort of like Valley Girl Terminators...) They can now sustain ...
2answers
547 views

### Missing checkmates in one

Have you ever missed a one-move checkmate and immediately realized it after making your move? If you have, you just might have what it takes to crack this problem. Let's take an example: g4 e5 ...
1answer
298 views

### Functional Equation: Squeeze it

Determine whether there exists a function $f:\mathbb{R}\rightarrow\mathbb{R}$ such that $$f\big(x^3+x\big)\le x\le\big(f(x)\big)^3+f(x)$$ for all $x\in\mathbb{R}$. Source: Math Excalibur Volume 22 No....
1answer
522 views

### Connect the wires without setting off the bomb

You just saw a planted time bomb! Just 5 minutes are remaining until it explodes and as you are in currently in a rural area (no bomb disposal squad) and you know how bombs usually work it is up to ...
2answers
296 views

### Happy days alphametic

Every letter a decimal digit, different letters for different digits: HAPPY HAPPY HAPPY + DAYS ---------- AHEAD Which digit does each letter ...
1answer
370 views

### The Lucky Number

Lucky numbers are 4 digit numbers that have the following property: they are equal to the sum of the fourth power of their digits. Therefore, they can be expressed as follows: 1000a+100b+10c+d = a^4+...
1answer
313 views

### Not the “SEND MORE MONEY” alphametic

There is a story that a poor college student sent a telegram with the words "SEND MORE MONEY" to his parents, asking for more money, and asking to fill in each letter with a different digit in order ...
3answers
332 views

### Where art thou, oh native rooks?

Here’s a tough puzzle for you all today! Given that both White and Black conspired to reach this position as briskly as possible, where standth White’s native rooks (the one from the starting ...
1answer
213 views

### One to Eleven Sum to Twenty Five

From the picture shown below, deduce the missing numbers (one to eleven)... none of them repeating. Four Numbers surrounding the Five diamonds A, B, C, D, E, as well as the five numbers in the outer ...
2answers
211 views

### An almost Shakespearian alphametic

Every letter stands for a digit in base-9 representation, different letters stand for different digits, and leading digits are always non-zero. ...
1answer
290 views

### A new year's mathematical mystery

Sam, Magnus, and Olivia each try to write the number 2020 as the sum of consecutive positive integers. They each use more than one integer, a different number of integers to the others, and none of ...
1answer
283 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 ...
1answer
484 views

### Find The Common Pattern In These Words

You are a super spy, typing on your QWERTY keyboard, when suddenly you received an urgent call from your boss, Caesar. He had urgently called you, defying all protocols, as he wanted to inform you ...
2answers
169 views

### 4x4 grid equations version 2

I decided to make another one of these, because they are fun and this one is rather different. Can you place all numbers from 1 to 16 into cells, such that the following 8 equations hold? Note that ...
1answer
276 views

### Multiplying to reverse digits

Today I noticed that $294$ is a multiple of $49$, which is the last two digits of $294$ reversed. How many other numbers have this property? That is, how many three-digit numbers have a factor which ...
2answers
683 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 ...
1answer
294 views

### H-one-one-oneycomb

What path could a honeybee follow to fill all cells with honey, beginning and ending at the center and visiting every cell exactly once? At first the only ...
5answers
1k views

### A few word puzzles 1

Here are some short word puzzles. 1) What's a not uncommon 7 letter word containing all 5 vowels and "s" and one other consonant (not necessarily in order)? 2) What's a common one syllable word, ...
3answers
598 views

4answers
483 views

### The broken wheel

In a regular polygon, we can connect six of the vertices to form a convex hexagon. I construct a hexagon by picking six vertices out of a regular $n$-sided polygon. In this hexagon, if you connect the ...
2answers
637 views