Questions tagged [mathematics]

A puzzle related to mathematical facts and objects, whose solution needs mathematical arguments. General mathematics questions are off-topic but can be asked on Mathematics Stack Exchange.

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6
votes
1answer
202 views

What's the graph relation? #2

What's the relation that joins the nodes? Open the image in a new tab if you'd like to see the diagram with better resolution. Previous What's the graph relation? #1 Hint 1
4
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1answer
94 views

What's the graph relation? #1

What is the relation that connects the nodes of this digraph?
3
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1answer
77 views

Name that node #2

What is the value of the unknown node? Previous Name that node #1 (Beginner's Level Puzzle)
5
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1answer
69 views

Name that node #1 (Beginner's Level Puzzle)

While Puzzling.SE has some extremely clever and difficult puzzles that are being solved by people whose intellect amazes me, I wanted to make some graph puzzles that were specifically meant for ...
3
votes
1answer
143 views

Decode the number to get a color!

These numbers in some way represents 4 commonly used colors: 25536, 187669382, 3043469, 11599 Can you decode it? Include the answer and your thought process to get the check mark. Let me know if you ...
5
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3answers
315 views

A simple children's riddle

Here is a riddle written on a cup: Eh is four times as much as Oi, Oh is four times as little as Ai, What do you get if you add all four of them up? Source: Russian Olympiad Problems, ...
2
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0answers
130 views

Minimum number of clues required for a 16 x 16 Sudoku

It is well-known that the minimum number of clues that completely specify a 9 x 9 Sudoku is 17. What is the minimum number of clues required for a 16 x 16 Sudoku whose cells contain one of the ...
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2answers
134 views

Burger and chips calculation puzzle 2 [closed]

This is easy though I think it is very fun to think about! S+S+S=30 S+H+H=20 H+F+F=9 H+F*S=?
4
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1answer
171 views

Colourful puzzle

Can you find appropriate number to complete this puzzle? :D Also, don't forget to consider colors given to each grid. They will help you a lot to find final answer.
1
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0answers
33 views

Use all of the following symbols and numbers in one equation for the result to be equal to 10 [duplicate]

Use all of the following symbols and numbers in one equation for the result to be equal to 10 (14, 12, 9 , 7, 3) (÷ × - +)
0
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1answer
110 views

Calculation puzzle 004

20 ~ 32 = 100 22 ~ 19 = 25 81 ~ 50 = 81 24 ~ 22 = ? Possible answers: 225, 196, 121, 625 or 400. I saw this question on the internet, these question types are YÖS exam questions and as seen from ...
0
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1answer
180 views

Mathematical puzzle 003

I saw this question on Math group and tried to solve it question to no avail. I approached it by taking the square of the first row, adding it to the second, then subtracting the fourth row from the ...
12
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1answer
475 views

What exclusive club is this?

You stumbled across a letter accidentally sent to you. It bears an official looking (though archaic) seal and the contents are as follows: TO whom it may concern: Thank you for your interest ...
3
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2answers
116 views

Mathematical puzzle 002

7 # 4 = 5 1 # 1 = 2 3 # 2 = 5 4 # 3 = ? Possible answers: 1, 2, 3, 4 or 5 In this puzzle, I tried to take square of each number and subtracting them or adding them, for instance 49 + 16 = 65 (...
6
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4answers
1k views

What is larger than largest, your intuitions are tarnished. (What am I?)

You might call me a number, but that would be a blunder. In class you may have been told otherwise, but I tell you now that those were all lies. I'm in the deck of the cards, as big as them come. ...
0
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1answer
92 views

Mathematical puzzle 001 [closed]

18 ~ 21 = 9 45 ~ 90 = 0 16 ~ 12 = 4 67 ~ 12 = ? I tried to solve it by taking LCM of each number, square rooting them, adding each digit, multiplying them and many other ways. However, I couldn't ...
2
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2answers
106 views

A complex matter of relations (What am I?)

There is many-a-kind of number, which sometimes makes me feel dumber. Let's say that we start from zero to four, and see if that leads us to learn some more. Some numbers you might see as a ...
6
votes
2answers
137 views

Use all of the following symbols and numbers in one equation

Use all of the following symbols and numbers in one equation for the result to be equal to 10 (14, 12, 9 , 7, 3) (÷ × - ÷)
4
votes
1answer
101 views

Which node(s) does 0 connect with in this simple graph?

If we add 0 as a node to the graph below, which node(s) will it connect to? Hint 0 Hint 1 Hint 2
9
votes
2answers
181 views

A constant gaze

What this infinite spiral seems to be gazing at goes without saying. Yet, to go on and on heedlessly as if trying to prove something, let’s just say it represents an equality with a well-known ...
0
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2answers
145 views

Please solve this number puzzle [closed]

This is a puzzle for logical minds. Please explain me the answer, with steps.
3
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1answer
172 views

Today I give you a mathematical pleasure, which you might want to take up and measure (What am I?)

Today I give you a mathematical pleasure, which you might want to take up and measure. With a pole, or a hole, oh well, you might want to read up on Borel. My spirit can always be found in myself, ...
20
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2answers
499 views

A real time-waster: the clock of confusion and color

John was doing his math problems like a good child one day until he looked at the clock to see if it was time to sleep. To his dismay, the blasted thing had become another math problem! But this one ...
8
votes
0answers
290 views

I'm a number with a special product, so name me when you think you've got it

In the blocks that come before, their special product tells us more. To guess my scheme you'll need calculation, but only little tests of recreation. Each block contains atoms strong as Thor, ...
1
vote
1answer
134 views

Make the numbers 1-100 using 8 8s

Rules: Make the numbers 1-100 using eight 8s Use the operations + - * / exponentiation and ! No Rounding as in $(\sqrt{88}+8*8+8+8+8)/8= 12$ No using other digits Multi digit numbers ...
14
votes
8answers
4k views

How to get 32 by using +1 , +1 , ×3 , ×3 , ÷2 , ÷2, ^2, ^2?

How to get 32 by using +1,+1,×3,×3,÷2,÷2,^2,^2? (The last two operators are 'squaring'.)
2
votes
2answers
169 views

Make the numbers 1-100 using six 6s

Rules: Make the numbers 1-100 using six 6s Use the operations + - * / exponentiation and ! No Rounding as in $((6 - (6 + 6) / 6) + 6!!) / 6 = 9$ No using other digits Multi digit ...
0
votes
1answer
235 views

What's the number in the last node of this directed graph?

Hint 1 Hint 2 Hint 3 Background on puzzle (Spoiler Alert)
11
votes
1answer
426 views

Which node(s) does 16 connect with in this simple graph?

If we add 16 as a node to the graph below, which node(s) will it connect to? Hint 1 Hint 2 Hint 3 Hint 4 Hint 5
16
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1answer
1k views

What node does 11 point to?

If we included 11 in the diagram below, which node would it connect to? Hint 1
13
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2answers
243 views

Cryptic Crossword?

You pick up a discarded newspaper, hoping to satiate your need for puzzles with a cryptic crossword. But as you turn to the page, you feel something is awry – perhaps some elision? Across 3. $F_6,F_7,...
1
vote
0answers
55 views

Find the rule: operation of 2 digits [closed]

It is a math riddle(rule finding). A friend of mine asked me whether I can find a rule for following operation * (He said that he doesn't know the answer) ============================================...
3
votes
2answers
278 views

Numbers 1-9 All used up?

There are nine numbers from one to nine. Each are to be used only once. Take two numbers from them to make a 2-digit number. It is multiplied by a different single digit no. to get a 2-digit ...
2
votes
1answer
76 views

Pandigital Puzzle

Can you find the 10 digit number* which contains each of the digits 0-9* exactly once, and when divided by 9 the quotient is a perfect cube which has the digit 7 in it exactly twice*? *in its base 10 ...
18
votes
1answer
575 views

A remarkable musical ode

On his deathbed, the great blind composer Charles Triangle composed the following remarkable piece, but his penchant for puzzles has left critics in tears searching for a deeper meaning to a piece ...
9
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2answers
251 views

The Two Thieves

Fatty and Skinny are two thieves, who stole gold coins and now divide them between themselves. Skinny says, “That’s unfair, Fatty, in your bag there are three times more coins than in mine.” Fatty ...
9
votes
2answers
599 views

A rectangle in a rectangular hole

I have a carpet of 240 inches by 120 inches, but my floor, which it needs to cover, is 180 inches by 160 inches. How can I do this by cutting the carpet into exactly two pieces? Source: Rational ...
-4
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1answer
84 views

@Math masti 1234567 [closed]

—+—=8 × — ×—=9 = = — 5 Solve this plz
4
votes
1answer
219 views

The motorcyclist's challenge

Three passengers $1,2,3$ starts out moving at constant speeds from $A$ to $B$. At the same time, a motorcyclist $M$ starts out from $B$ towards $A$ to pick the passengers up. As illustrated below: ...
14
votes
6answers
4k views

Guess a number between 1 and 16 with 7 attempts

How to guess a number between 1~16 in 7 attempts? The person who answers the question CAN either lie once or never. Can you make the proper 7 questions to guess what number between 1–16 will be, and ...
6
votes
1answer
495 views

Who's that Simple Pokémon™?

For every alphabet (A to Z), there exists at most one corresponding Simple Pokémon™. As of Generation 8, it goes: ...
6
votes
0answers
133 views

Is it possible to create a knot that is locked only when the rope is stretched?

Is it possible to create a knot that is stable/locked when the rope is stretched? When the tension is relived the knot should open.
10
votes
2answers
983 views

First digit of 2020!

This is a follow up to First digit of 3^2020 Can you find the first digit of 2020! (factorial) without a computer?
4
votes
2answers
289 views

The Genius Bank Robber

StackVille Bank & Trust - Robbed! The Robbery The bank is being robbed. There are millions in cash in the vault. The lone robber takes the manager to the safe and demands he opens it. The ...
33
votes
3answers
5k views

First digit of 3^2020

Inspired by The last digit for 3^(2019) Can you find the first digit of $3^{2020}$ without a computer?
2
votes
1answer
151 views

Exceptional numbers, neither good nor bad

Behold, my new comrades, a monstrous yet straightforward puzzle, appearing on the order of that group of fellows occasionally visiting PSE but hitherto unable to join their simple friends. I assure ...
1
vote
1answer
166 views

UFO in a hurry #1: land at a power plant

A UFO is at one kilometer altitude, and one kilometer due east of a power plant on the ground it wants to investigate. The UFO has infinite acceleration but is limited to a speed of ( altitude + 1km )...
6
votes
7answers
1k views

Five minutes puzzle: Multiway switches

Here's an easy puzzle that should take you only five minutes to solve, inspired by my hallway. Most intuitive answer get the mark: Six switches control the same light bulb in a multiway switching ...
1
vote
2answers
279 views

The Missing House Number

The Visit One day I was visiting my sister in Boston and heard a bunch of kids yelling and playing in the yard ( yahd ). I couldn't see the kids, and hadn't seen my sis for years so I asked her, "...
7
votes
2answers
1k views

What is the missing number and the correct sequence?

I have a riddle, you might wanna help solve. Just imagine, we would like to change the sequence (that works very well now [in German there is the term "funktioniert 1A" - which translates into ...

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