# 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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### 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 ...
9k views

### Ten girls around a table

Ten girls are sitting around a table. Each of them picks a real number and whispers it to the two neighbors immediately to the left and to the right. (Hence: each girl communicates one number, and ...
349 views

### Flock of Geese alphametic

In each of the following three alphametic puzzles, every letter stands for a digit in base-10 representation, and different letters stand for different digits. Leading digits are always non-zero. <...
2k views

### Divisible by seventeen

Determine the smallest integer $n \geq 0$ for which the decimal digit sum of n is a multiple of 17 the decimal digit sum of $n+1$ is a multiple of 17. No computers! The puzzle has a nice direct ...
251 views

### French alphametic (corrected)

This is the corrected version of puzzle French alphametic (misspelled) Every letter stands for a digit in base-10 representation, different letters stand for different digits, and the four ...
283 views

### French alphametic (misspelled)

The following puzzle has a spelling mistake: DOUCE should be DOUZE. The correct version is: French alphametic (corrected) (Surprisingly the faulty version allows feasible solutions.) Every ...
218 views

### Neil Armstrong and Buzz Aldrin alphametic

Every letter stands for a digit in decimal representation, different letters stand for different digits: MEN + CAN = REACH - MOON Which digit does each ...
203 views

### Nebulosity alphametic

Every letter stands for a digit in decimal representation, different letters stand for different digits: ...
165 views

### Wheat field alphametic

Every letter stands for a digit in base-11 representation, different letters stand for different digits: WHEAT + FIELD ------------ FARMER ...
305 views

### Happy days alphametic

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

### Baseball games alphametic

Every letter a decimal digit, different letters for different digits: BASE + BALL -------- GAMES Which digit does each letter represent?
435 views

### E's-y Word-Square Fill-in

Not necessarily easy, but "'E's-y"! For each word square below, the Es have been filled in for you. Your task is to complete the rest of the square using only ...
762 views

### I Was Told It Would Explode

Story: There is a line of bombs, all over a building. You are the bomb defusal expert, and you are the one everyone is counting on the save the city, for as if any one of the bombs go off, you, and ...
231 views

### Crossing out a digit

Find the largest integer $N$ whose decimal representation has the following properties: The rightmost digit in the decimal representation is not $0$. There exists a digit $d$ in the decimal ...
574 views

### Social networking “party” system

A party is a group chat, the only difference being there's a "leader" (this is the person who started the chat) In these parties, there can only be 5 maximum users, this includes the leader. In ...
173 views

### Increasing rows and columns

Cosmo has arranged the integers $1,2,\ldots,49$ in a $7\times7$ table, so that in each row (left to right) and in each column (top to bottom) the entries occur in increasing order. Questions: ...
2k views

### A sloppy calculation

Little Johnny Red forgot to write the multiplication sign between two 3-digit numbers $x$ and $y$ and simply wrote them as one number. When Johnny's teacher graded the homework, it turned out that the ...
519 views

### Longest $Scramble Sentence$? [closed]

Before we begin, allow me to define what I call a Scramble Sentence, A Scramble Sentence is a grammatically correct sentence, where at least 1 other permutation, of the letters in the sentence, ...
3k views

### Can you stop the rambling rook?

This is a chess puzzle someone showed me a long time ago. If you already know this puzzle please give the others a chance to solve it first. This puzzle was originally created by Otto Gallischek and ...
720 views

### What is the Key to Good No-Computers Puzzles?

Question What advice, strategies, keys, or elements would you suggest for creating challenging puzzles that aren't (reasonably) computer soluble? Details I'm a programmer, so I can appreciate the ...
4k views

### Find the longest string of words such that the (4 letter) end of one word is the start of the next

Here is an open-ended challenge. Find the longest series of English words such that the final four letters of word $n$ are the same as the first four letters of word $n+1$. Example (3 words) ...
832 views

### A Four Liner of my Own: I'm counting on you

With all the popularity of four liners lately, I figured I'd contribute. Since my recent riddles seem to have been too hard, I'll err on the side of ease this time. Determine what each line is ...
4k views

### Two dead beans on a stone

Samuel Bean, a Canadian doctor, had a tombstone erected in Rushes Cemetery near Crosshill, Wellesley Township, Ontario, for his first two wives, Henrietta and Susanna. The original stone was carved in ...
1k views

### The magic of the primes

A mathematician, a physicist, and an engineer found themselves caught in an ancient anecdote. Lacking a chemist to brew them an anecdote antidote, they fell to arguing over which of them was to be the ...
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 ...
2k views

### How is it possible?

I have been captured, then shot, framed and hung. But luckily, I am not dead. How is it possible? Disclaimer: this puzzle is inspired by real world observation, so no alien lifeforms, super heroes ...
721 views

### Complete the world's longest self-documenting sentence

Complete the following by filling in the blanks with written numbers to create the world's longest self-documenting sentence. ...
456 views

4k views

### Solitaire Chess

A friend of mine got me Solitaire Chess for Christmas years ago. I set up the board below. Is it possible to solve it? If so, what is the solution? (No programs allowed- Use only your brain.) Rules: ...
1k views

### Hangman- No misses left

**** No programs allowed. You must find the answer using your own brain. **** Your hangman game allows for 9 misses, but on the 10th miss, you're hanged! You don't want to be hanged. The letters ...
831 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 ...
In the number $(1+\sqrt{3})^{2015}$, what is the 224th digit after the decimal point? You may NOT use a calculator, computer, or any electronic aid to answer this question. Only pen(cil), paper, and ...