Questions tagged [no-computers]

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

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12
votes
3answers
2k views

Want to go from MANILA to UGANDA

How do you get from the word MANILA to UGANDA in the shortest time? You can change up to 3 letters at a time to form a new 6 letter word which MUST be either a Country name or a Capital of a country. ...
12
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4answers
1k views

The Special Numbers

Let's try to find out the numbers satisfying the cryptarithms below; $ab=(a+b)^2$ $abc=(a+b+c)^3$ $abcd=(a+b+c+d)^4$ There are only 3 unique answers! Note: $a$,$b$,$c$,$d$ are all ...
12
votes
4answers
865 views

Find the three digit Prime number P from the given unusual relationships

$Given:$ P is a 3 digit prime number Q,R,S,T are distinct digits( 0 to 9 ) QRS is a concatenated number $Relationships:$ $P$ = $QRS + T$ = Reverse of $( QRS * T)$ Find P using just ...
12
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2answers
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? ...
12
votes
2answers
360 views

Cannibalistic Words

Drawing from the word pool below, find the twelve Cannibalistic Words. (Note the no-computers and logical-deduction tags.) WILD _ _ ☐ _ _ _ _ ☐ PENS ☐ _ _ _ _ ☐ _ _ DEED _ _ _ ☐ ☐ _ _ _ BLED ...
12
votes
3answers
1k views

One year celebration

I've got notified a few days ago from PSE that my account on this website is 1 year old. So I thought about celebrating it (or commemorating it, because you all made me addicted to this) with a puzzle ...
12
votes
1answer
396 views

Infinite Sequence based on Simple Rule

Using one simple rule, an Infinite Sequence has been developed. First 30 terms are given. Can you continue the sequence for at least next Ten Terms? Series continues from top left to bottom right. $...
12
votes
2answers
2k views

My Graph Theory Students

I have 18 students in my graph theory course this semester: Anne, Bernard, Clare, David,..., and Rachel. At the start of the course I asked them to draw the graph below, in which each of them is ...
12
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2answers
785 views

Hearts and Spades in a Row

From a deck of playing cards remove hearts ace to seven, and spades ace to seven. Now place them on a table in a row so that the number of cards between the two aces is 1, the number of cards ...
12
votes
2answers
1k views

Alphabetical Sudoku

Who loves fish? Okay that might sound a bit weird but don't worry, I am still sane. Maybe. To answer the question you must complete the Sudoku below. A word will appear in the highlighted box which ...
12
votes
1answer
467 views

Resolve this Fibonacci Relationship

$Given$: $A$, $B$, $C$, $E$, $F$ are distinct digits varying from $1$ to $9$. $A$ is a Fibonacci number. $BB$, $BC$, $EF$ are concatenated Numbers. $Relationship$: $(A*BB)*(BC)^2$ = $(EF)^2- B$ ...
12
votes
2answers
428 views

Comparatortionist: The $M_Q$ Functor

The Problem At the intersection of mathematics, computer science, and insanity, we find the $M_Q$ functor${}^1$. $${M_Q} = {\Phi _{{s_1},{s_2}}}\left\{ {\begin{array}{*{20}{l}} {E \leftarrow {\Phi ...
12
votes
1answer
305 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. ...
12
votes
1answer
502 views

A broken mosaic of words

In this puzzle, you'll have to rebuild words using the "pieces" listed at the bottom and place them in the grid provided below. Some notes about this puzzle: The gray cells with the dotted border are ...
12
votes
4answers
379 views

This word is a name. Also a Surname

Starts with a place, ends with a place Starts with a number, ends with a number Starts with a surname, ends with a surname A word to the wise. Only one vowel- used twice. Can you guess,...
12
votes
1answer
186 views

This compound word is a fun thing

Here is an interesting compound word It has all the 5 vowels but used only once (no repeat of the same vowel) It has 4 consecutive words that include 2 names. It starts with a name and ...
12
votes
1answer
227 views

An alphametic for René Descartes

The best known philosophical statement by René Descartes is "Cogito ergo sum" (French: Je pense, donc je suis; English: I think, therefore I am). ...
12
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2answers
531 views

KenKen Zen: A journey begins

Let us shy away from the materialistic opulence of 361- cell KenKen layouts (−9 to +9, squared).  Let us contemplate a modest KenKen journey, unburdened by gratuitously ...
11
votes
4answers
4k views

Use 1 9 6 2 in this order to make 75

I'm looking for a solution to make number $75$ with numbers $1$ $9$ $6$ $2$ in that order and the same rules as in Use 2 0 1 and 8 to make 67. Here a copy of those rules: You must use all 4 digits. ...
11
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7answers
1k views

Fill in the boxes to get the right equation

Here is a math puzzle I had a little bit of hard time with No computers please There is a solution without inverting 6 to 9
11
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6answers
2k views

Coke alphametic

The only thing I love more than Coke is numbers divisible by 73. I claim I have found a unique assignment of distinct digits $0,1,...,9$ to the symbols $ C, O, L,$ and $A$ such that $73$ divides the ...
11
votes
8answers
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 ...
11
votes
2answers
2k views

Here's another Color Logic problem

Find the rule specified in the image below. Note that the rule applies to each row independently so every "true" row is "true" by itself If you are confused about these, here's an easy one: Did you ...
11
votes
3answers
684 views

Three positive integers

Find the smallest possible value of $ab+c$, where $a,b,c$ are positive integers with $a+bc=2016$. (No computers! The puzzle has a nice direct solution.)
11
votes
3answers
639 views

Five Powers of Fives Produce Unique Pandigital Number…Solve for X..Tell me Y

Given: Y is a Pan-digital Number (no zero, 1 to 9 only) ending in 3. Pan digital number consists of all 9 digits 1 to 9..each digit occurring only once as is the case here. Last digit is given as 3 ...
11
votes
2answers
759 views

Happy 2017 Sudoku

This is a simple Sudoku. The only thing different from a regular sudoku are the symbols used: HAPY2017*. The snowflakes (a.k.a. asterisk) are like any other character. Wishing you a Happy New Year ...
11
votes
2answers
496 views

Ziggy - Make a square from 8 polyomino pieces

A few years ago I created a small packing puzzle that I'd like to share here today. The puzzle is based on the fact that $1+2+3+4+5+6+7+8 = 6^2$. It consists of 8 zig-zag polyomino pieces, ranging in ...
11
votes
1answer
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 ...
11
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1answer
3k 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 ...
11
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1answer
307 views

Don't look back, crazy clown

Start with these two words INSANE RETROSPECT and see if you can get them to exchange places by transferring one letter at a time. With each ...
11
votes
1answer
521 views

Professor Roman gives unusual math quiz ahead of

His usual Monday Morning 8am class. This is for extra AAA credits. $A$, $B$, $C$ are distinct digits. $AA$, $BA$, $BBAAA$, $CBBBAB$ are distinct numbers. Please deduce these with concise reasoning ...
11
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1answer
410 views

Watch the video and figure out who stole the documents?

Ms. Shipra is a renowned scientist in TIFR, Mumbai. She recently discovered a new way of gaining huge energy from the water-current at a much lower cost. Considering its future application, many ...
10
votes
7answers
2k views

Last Digit of Multiplications

I have 4 different 1 digit positive integer numbers $(a,b,c,d)$. than I apply this formula $random(a,b,c,d) × random(a,b,c,d) × ... × random(a,b,c,d)$ the last digit of the result is always one of ...
10
votes
4answers
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 ...
10
votes
4answers
2k views

What's the most rewarding path?

Get from the top-left to the bottom-right using only right and down moves. Pick up as much gold as possible. There is only one maximum.
10
votes
3answers
2k views

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 ...
10
votes
3answers
1k views

A String-based Puzzle: Can you get from the string “baa” to “bacaccacacccc”?

Goal: Go from the initial string to the final string by applying a sequence of string replacement rules. You are given the following: Initial String - baa Final String - bacaccacacccc You ...
10
votes
5answers
1k views

Consecutive Numbers Sum of a number

Consecutive Numbers Sum (or $CNS$) is the number of different consecutive positive integers' summation resulting to a specific number. For example; $CNS(45)=5$ $22+23=45$ $14+15+16=45$ $7+8+9+10+11=...
10
votes
4answers
334 views

Choo-choo! Word trains

All aboard the Word Train Express! Engineering a word train is simple: I'll give you the locomotive (the first word) and the caboose (the last word), and I'll specify the number of boxcars (...
10
votes
2answers
3k views

How many Strobogrammatic numbers are there from 0 to 99999

0,1,2,5,8,11,69,96 are Strobogrammatic numbers. We call a Strobogrammatic numbers if: When it is typed on a calculator, and the calculator is spun 180 degrees, the number visually looks the ...
10
votes
2answers
411 views

Riley Riddles in Reverse, third helping

Once more! For science! Here's yet another batch of "inverted" Riley riddles. The idea is still exactly the same as before: You get three words. You must find one solution word that you can ...
10
votes
2answers
844 views

An ugly formula [closed]

Our teacher wrote the following ugly algebraic formula on the blackboard $$(n+\sqrt{n^2-1})^{4/3}+(n+\sqrt{n^2-1})^{-4/3}$$ Our teacher told us that for some positive integers $n$ this ugly formula ...
10
votes
5answers
1k views

Knight on the keyboard

You are given a QWERTY keyboard, and are allowed to choose where you wish to start. You are only able type in the same way a knight is able to move on a chessboard (but in this case, on the keyboard). ...
10
votes
1answer
466 views

100 Years of GCHQ - A quick afternoon puzzle!

I'm off to the Science Museum London tomorrow, to the Exhibition celebrating 100 years of GCHQ. As such, they sent me a little reminder email this afternoon. On the bottom of the email was the ...
10
votes
1answer
300 views

Geographic alphametic riddle with European flags

Every letter stands for a digit in base-10 representation, different letters stand for different digits, and leading digits are always non-zero. $\quad$ PLUS $\quad$ $\quad$ IS EQUAL TO $\quad$ ...
10
votes
3answers
301 views

Four hand tiled squares demonstrating a Pythagorean Quadruple

Demonstrating the Pythagorean Quadruple $6\times6 + 6\times6 + 7\times7 = 11\times11$ Using the pieces shown in the $11\times11$ square: The objective: Arrange the pink pieces (four enneominoes) ...
10
votes
1answer
486 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 ...
10
votes
1answer
392 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 ...
10
votes
1answer
492 views

Labelling a graph with a partition of 100

Label the vertices of this graph with positive integers (repetitions allowed) whose sum is 100 in such a way that any pair of vertices are joined by an edge if (and only if) they have labels with a ...
10
votes
1answer
931 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? ...

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