Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

Questions tagged [mathematics]

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

2,720 questions
Filter by
Sorted by
Tagged with
538 views

National Graph Lottery

In UK's National Lottery players choose 6 different whole numbers in the range 1 to 59, and win a large prize if all six match with the day's draw. Each choice of six numbers by a player gives rise ...
145 views

What is a Dial Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles. If a word conforms to a special rule, I call it a Dial Word™. Use the ...
228 views

Which is the missing number?

I am working on this puzzle since last week. 01 ?? 05 12 10 13 15 09 14 02 08 03 04 07 11 06 which is the missing number ?? note : answer is not 16
305 views

Did you know that a prime, regardless of its base, is always a prime? I am looking for a prime. It’s the largest of its kind. In solving this puzzle, the answer you may find. ...
546 views

Winning the Lottery

Bob: I hear you won the lottery. Alice: So I did! Bob: What six numbers did you win it with? Alice: Can't remember. All I recall is that they were all different, and none greater than 28. Bob: ...
996 views

Squares inside a square

Distribute the digits from 1 to 9 to a 3x3 square, such that you reach as many square numbers as possible. A valid square number in the 3x3 square is either a single digit square number or is build ...
479 views

What is a NaturaW Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles. If a word conforms to a special rule, I call it a NaturaW Word™. Use the ...
729 views

What is a CirKle Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles. If a word conforms to a special rule, I call it a CirKle Word™. Use the ...
2k views

Many many thanks

The alphametic MANY + MANY = THANKS has no solutions in base 10. How many more "MANYs" must I add before it has a solution?
578 views

Which Numbers Replace the Question Marks?

Can you find out what the numbers below have in common? Can you figure out what comes next? ...
152 views

Greedy for Cash

Solve this Cryptarithm GIVE + MORE --------- MONEY Referenced from the Britannica Encyclopaedia No. 25 - "Number Prague"
435 views

'The Imperial triangles' trigonometry question

There is a very well-known family of right triangles in Mathematics called "The Imperial triangles". Let me explain you how they are defined: We say $T_n$ is the $n$-th Imperial triangle if these two ...
384 views

Minimum number of tries to find the balance!

There are 8 distinct weights and a two-pan equal arm balance scale, and you know the weights' weight order: the lightest is numbered as 1 and the heaviest is numbered as 8 and the rest accordingly. ...
16k views

Get 100 as an answer on a calculator without using 0

Task Get 100 as an answer with only four keystrokes on a regular calculator. Disallowed keys 0 00 Allowed keys All other than the aforementioned two keys. Take the below image as a reference. ...
158 views

Trying to figure a math puzzle/equation for a surprise trip using the date [closed]

I planning a surprise trip for my husband's 40th. He is a math geek. I am not. My plan is to tell him in a series of riddles/puzzles that he needs to figure out. We are going to LA to see his ...
185 views

What are the house numbers?

Following the last question " What is the corner house number?" here is possibly a more challenging version. Fill in the missing house numbers on the map shown below. The area is occupied by math and ...
262 views

map 5 unequal ranges to id

This is actually coming from a business place, but it's all about being able to do math tricks, and that's why I'm posting here. I want to implement the following function: ...
674 views

Ernie and the Superconducting Boxes

I was in anticipation all last week. Ernie, who had been travelling for several months, was finally coming home. So over the weekend I dropped in on him. He was bursting with news. "Some wonderful ...
2k views

A Magic Diamond

Place 15 different positive integers on the vertices of this graph so that the ten products of three numbers in a straight line are all equal.
165 views

Hunting for treasure in 1-d grid [duplicate]

In a castle, there are N rooms in a line. Each room has a door to the two neighbouring rooms (or the one neighbouring room, for the rooms at either end). A treasure is hidden in one of the rooms. ...
1k views

2k views

Missing Piece of Pie - Can you find it?

A piece is missing! What should it be?
510 views

we are five we have three thousand four hundred fifty who are we? [closed]

we are five we three thousand four hundred fifty, who are we ?. Its a riddle like question but stranded with getting the answer for this question , am very sure the answer will make me slap my head ...
255 views

5 Precommitting Pirates Puzzle

Another variant of the Pirate Puzzle, inspired by this variant and a bit more complex. Scenario: Five pirates of different ages obtain 100 gold pieces in total, and want to decide how to split them. ...
83 views

Complete the series on this set of numbers [closed]

Here is one that I can't seem to solve: Complete the following series: 529, 531, 542, 544, 561, 558
255 views

Minimize sum of guesses to win lottery

Ten boxes are given with $a_1,a_2,a_3,a_4,a_5 ......a_{10}$ number of balls in them respectively .These boxes are randomly ordered but $a_1,a_2 .....a_{10}$ is told.We can arbitrary select a box and ...
How do you make $21$ from the numbers $1$, $5$, $6$, and $7$? You can use the operations of addition, subtraction, multiplication and division, as well as brackets. You must use each number exactly ...