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.
5,517 questions
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numbers inside a plane tiling [closed]
Is it possible to place exactly one positive integer in each shape such that the following conditions hold?
Only the number $1$ is repeated.
Each dodecagon's number is the product of the numbers in ...
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Can a 10*10 square be paved with 1*4 rectangular stone plates?
Can a 10 * 10 square be paved with 1*4 rectangular stone plates?
I seek a very intuitive and simple answer to this puzzle.
P.S. Will post the source later. The source contains the answer but it is not ...
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Where in the world is the chicken?
Along her journey, the chicken asked an indecisive donkey,
“Can I do it?”
After a long deliberation, the donkey finally answered:
“Seek the Still Green Desert. The skeleton upon the dune has your ...
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Two unique birthdates
My Dad loves math riddles.
He said to me, “You know your late Grandma and her first cousin were both born in the same year and on a Friday. Grandma Hannah Prime was several months older than her first ...
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Fake Palindromes
A positive integer is a fake palindrome if it is not a palindrome but its prime divisors are precisely those of the number written backwards.
a) Find the first dozen fake palindromes.
b) Are there ...
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How can I generate all unique number combinations that sum to a target value in JavaScript? [closed]
I'm trying to implement the classic Combination Sum problem in JavaScript:
Given:
candidates = [2, 3, 6, 7]
target = 7
I want to get:
[ [2, 2, 3], [7] ]
I’m mainly confused about:
how to avoid ...
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Can a number have the same digit sum and digit product?
I was exploring digit patterns and wondered whether there are positive integers whose sum of digits is exactly equal to their product of digits.
For example, for 123:
Digit sum = 1 + 2 + 3 = 6
Digit ...
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"Interlacing" the 8 Queens Problem
Let "attacking" mean protecting, but everyone says "attacking"...
Let $Q$ be a chess position with $q$ non-attacking queens, $R$ one with $r$ rooks, $B$ $b$ bishops, $N$ $n$ ...
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Find side view and simple 3d [closed]
You need to find a side view of B) nacrt=front view tlocrt=top view. You also need to draw the 3d model. I got this puzzle from my teacher in school.
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Complete the integer sequence: 10, 11, 12, 13, 14, 20, ?, ?, ?, ?
Here is a sequence I happened to work out, although I am certainly not the first one.
Can you fill in the missing numbers?
10, 11, 12, 13, 14, 20, ?, ?, ?, ?
NB: The sequence ends after the last ...
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Crossing a square pond with beams
Here is a classical mathematical puzzle:
In the middle of a square pond lies a square island (whose sides are aligned with the sides of the pond). On the island is a tower with a princess locked ...
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Regular pentagram inscribed in a parabola
The diagram shows a regular pentagram inscribed in a parabola.
Can another red pentagon (congruent to the one shown) fit in the gray region?
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Find all integers n such that the sum of the factorials of its digits equals ⌊√n⌋ [closed]
Find all integers n such that the sum of the factorials of its digits equals ⌊√n⌋.
For example, if n=2025, then 2!+0!+2!+5!=⌊√2025⌋, although this is not true.
How can you find all integers n that ...
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How do you get 5 by using the numbers 2, 2, 3 and 5?
You can use addition, multiplication, subtraction, and division as many times as you want but can only use the numbers one time each.
