**2.040 mathematics questions.**

$A^2$ + $B^2$, $AB$, and $A + B$ are all integers.
Do both $A$ and $B$ have to be integers? If not, what is an example where they are not?

My "friend" (who has absolutely too much time on his hands) made me a DIY Scrabble™ board. He's nice like that. He cut, sanded, painted and even routed out little cradles for the letter tiles.
Oh ...

Here's a crazy riddle for you.
Figure out what I am, if you can:
I'm gone before you know it,
yet I go on and on and on...
Can you tell me what I am?

I got "x" number of sweets. I can divide my sweets equally by 1,2,3,4,5,6,7 all the way to 101 friends such that I have no left overs. Find the least number of sweets I could possibly have at first?
...

A second maths puzzle!
$$\begin{align}0+0&=0\\1+1&=1\\2+2&=2\\12.2+6&=20\\12.3+6&=21\\9+(-3.2)&=-10\\7+(-1.1)&=-3\\0.95+(-0.95)&=-1\\e^\pi+(-\pi)&=\quad?\end{...

Mr. Accurado, a keen and sharp eyed professional thought of starting his special assignment at few seconds past midnight.
However due to a distraction- which lasted for less than a minute - he could ...

On a day during a severe winter, somewhere in cold countries, I watched a weather report on a television.
The report showed that on that particular day the temperature was 0° ....but due to some ...

I found this puzzle online:
On the top floor of a castle lives a princess. The floor has 17 bedrooms arranged in a row. Each bedroom has doors connecting to the adjoining bedrooms as well as to the ...

Use 2,3,4,5 and + - * / only once each (it's not necessary to use all of them) to equal 26.
I know 2 answers, but there is a 3rd (or more) :)

An adversary places eight white rooks and eight black rooks on sixteen squares of a chessboard, subject to these rules:
In any row, there must be exactly two rooks, one of each color.
In any column, ...

During a tournament, seven football teams, three European, three South American, and one from Africa, scored a total of 89 goals.
The number of goals scored by the African squad was relatively prime ...

So basically this is a complex deep web puzzle and we're pretty much stuck at it right now as we don't have any idea what this is about, any help will be aprreciated (the attached images are the ...

I have 100 (one hundred) bottles of visually identical water, exactly one of which is poisonous. In this experiment, the only test I can do is to let some mice drink it. If a mouse drinks the ...

I've been transported through a wormhole to a new planet in a new universe.
Standard stuff, really.
But something is... off about this planet. Sometimes, walking around it, I just feel like I'm ...

Mathematical Rebus I
Mathematical Rebus II
Small note on the first image:
Hint 1 for the squares image:
Hint 2 for the squares image:
Hint 3 for the squares image (alternative image that should ...

6 players sitting in a circle and each assigned a card among 2 Hearts, 3 Hearts, ..., Ace Hearts (i.e. any of the Hearts cards). Holding her card above his forehead (i.e. Indian Poker fashion), each ...

The sum of the whole is 25
Large and small are different by 4
The first is 2 times the fourth
Third is equal to first
What are the four numbers?
This is really bugging me can not figure it ...

What did I do yesterday ? Above image is the rebus.
Src : slightly copied .

For this most recent NBA season, ESPN.com has had in-game win probabilities:
My question:
Say a team gets a big lead and has a 90% chance of winning. What is the probability that at some point ...

Consider a situation in which two companies hold data about individuals: the first company holds individual's names, and their age.
The second company also holds the individual's name, but instead of ...

There is a magic transmuter which turns stones into the gold! But this transmuter works weird.
Every time you put a stone or more stones and press a button, it takes that stone into a slot in the ...

I heard this number sequence problem about 25 years ago from a maths lecturer.
What number should go in the place of the question mark in this mathematical sequence:
$..., 30, ?, 60, 90, 140, 225, ...

Recall the classic old problem where we're asked whether a line segment of specific length can be constructed with compass and straightedge, given an initial line segment of length 1? We're going to ...

You are given ten stacks of golden coins, each stack consisting of ten coins and a digital scale with arbitrary precision.
You know that all stacks of coins are made from gold, weighing 10 grams per ...

I have 9 coins that look identical, but one is heavier than the others. I want to identify that one.
My brother has an old-fashioned balance scale that I can use, but I'll have to do annoying chores ...

In the land of Puzzovania Sock Enrage:
More than 90% of the puzzles are tagged with both riddle and mathematics.
More than 90% of the puzzles are tagged with both riddle and logical-deduction.
Show ...

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Title based on this xkcd.
Your biggest dream has come true: you have an infinite supply of your favorite five-flavor candy button ...

Just made up a problem. Have ideas, but no proof yet – came here for professional help.
Tonight an important match of Metagame (box/football/baseball/chess) takes place. Everyone is hyped. Everyone ...

I was really happy for the fact that I won the inter-galactic best magician award. So I decided to throw a party of $n$ people (excluding me).
The people who came to that party was jealous, really ...

So large I am, you could not see,
Bigger than aught that you could dream.
I ate so much, I must lie down,
To lay the weight off you again.
You might think there's one of me,
A counter ...

You've got 25 horses and you can host races in groups of 5. You don't have a stopwatch, obviously. Then what should be the minimum number of races that you should be conducting so as to ascertain the ...

Here are linked clues:
An ancient alphabet
Related to an association between measures of a circle
Part of a title of an English movie of an auto-biopic
An abbreviated form representing loyal/...

N is a number where each digit is divisible by its place, for example:
1527
1 has to be divisible by 1, 5 divisible by 2, 2 divisible by 3, and 7 divisible by 4.
Additionally, N must be divisible ...

Engines numbered 1, 2, ..., n are on the line at the left, and it is desired to rearrange(permute) the cars as they leave on the right-hand track. An engine that is on the spur track can be left there ...

Note: Sorry, this puzzle almost similar with the last question:
The main purpose of this QUESTION is:
To know what types of this puzzle is exactly.
It is still can be solve if I remove the most ...

On my way to work each morning I pass a news-agency that usually has a sandwich-board displaying the latest headlines of a somewhat disreputable tabloid newspaper (not that I would ever buy such a ...

Actually these puzzles have been made by me two years ago, but I've made it easier and faster to finish by reducing the calculation operation.
...

What goes next in the number sequence?
9, 9, 10, 9, 10, 9, 9, 9, 5, 8, 6, 10, 11, 8, ?
Hint 1
Hint 2

This is a relatively straightforward little puzzle, but the answers are somewhat unintuitive or can prompt a new perspective. It might be an interesting little puzzle for a probability teaching ...

My friend Tim is a real dick. Whatever happens to him he just won't die! I asked him what the secret to his power was (So I could kick his ass). He handed me a crumpled up piece of this paper with ...

You have n students sitting in a line and you want to move them so that no student is sitting next to anyone they were originally sitting next to. What is the ...

You have recently caught
N Pokemon and you also have
M Pokemon candy bars. You can evolve any of your Pokemon by paying
X candy bars. Alternatively, you can sell any of your Pokemon for a price of
...

What are the next two numbers in the following sequence:
0, 1, 4, 18, __, __.
Please explain your logic.

Long ago (The year of 1350 BC), the aliens found the Earth. They saw our math, and tried to learn it. They completely failed at it, but the humans adopted their form of math. Now, in the year 2050 AD, ...

The sum of a three digit number (ABC) and another three digit number (DEF), where DEF is obtained by thoroughly shuffling* the original three digits of ABC, is 1000. Then, find all possible such pairs ...

You are given 8 equal sized bars of silver labeled a to h. You know for a fact one of them is fake, and the only measurable difference is weight. However you do not know if the fake bar is heavier or ...

Two players, $A$ and $B$, and the Casino play a game. It involves showing zeros or ones: each player picks $0/1$ and also the Casino picks $0/1$.
If the Casino and both players $A$ and $B$ show the ...

Let's consider Strategy to beat the Casino puzzle, but reverse it - fix number of losses and ask a question about amount of rounds:
Two players, A and B, and the Casino play a game. The game ...

Sir Isaac Newton's book "Arithmetica Universalis" contains the following famous puzzle:
In $4$ weeks, $12$ cows graze bare $3\frac13$ acres of pasture land, and
in $9$ weeks, $21$ cows graze ...

- logical-deduction
- calculation-puzzle
- geometry
- combinatorics
- strategy
- formation-of-numbers
- probability
- number-theory
- number-sequence
- optimization
- game
- pattern
- no-computers
- lateral-thinking
- visual
- weighing
- checkerboard
- story
- word-problem
- reachability
- riddle
- graph-theory
- enigmatic-puzzle
- computer-puzzle
- cipher

- Why are some coins Reuleaux triangles?
- What's the best side of the plane to see for arbitrary flights?
- Should I punish my teenage sister, whom I have full custody of, for lying to me in order to secretly see her boyfriend?
- Why does the Party allow playing chess in Orwell's 1984?
- Being alive today: the most improbable coincidence?
- Good worker, but she turns up late and leaves early, and others are gossiping
- Saying "No" to my brother's demand without causing an argument
- How does Linux identify users?
- Why aren't payloads their own fairings?
- Gender transition as a starting faculty member: a terrible idea?
- Why does c = ++(a+b) give compilation error?
- What does it mean to "burn a zero-day"?
- Travelling soon and lost UK passport. What can I do?
- How do I execute multiple commands using the same argument?
- How to limit the impact of and reduce the risk of SQL injection?
- How fast can I flood the Netherlands entirely and permanently?
- Food ‘fight’ in the Talmud
- Formality of the 2nd ordered configuration space of a closed Riemann surface
- What causes loss of power over lifetime of a magnetron?
- What's wrong in this method of solving a difference equation
- How can I express the time between late 80s and beginning of 90s (somewhere around 1988-1992)?
- Coworker demands immediate assistance when having computer trouble
- Dealing with a PhD student reneging on an agreement to appear in social media
- Was Newt ever referenced in the Harry Potter series?