Tagged Questions

Puzzles, curiosities, brain teasers and other mathematics done "just for fun".

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Strategy of ball math game

Found math game: http://www.emathhelp.net/math-games-and-logic-puzzles/rgbw/ What is a strategy for it? I can make 15 white balls max. Any thoughts?
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Trying to understand the properties of a combinatorial game

Consider the following game for $n \geqslant 3$, which I will demonstrate with $n=4$: draw an $n$-gon and place the value 0 at each of the vertices, except one vertex which we circle and place the ...
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The grey area is equal to the white area

Problem. Show that the sum of the areas of the white regions is equal to the sum of the areas of the grey regions. All the angles between consecutive chords are $45^\circ$. A solution (not totally ...
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Intuitive ways to get formula of binomial-like sum

Is there an intuitive way, though I am not sure how to find a conceptual proof either, to establish the following identity: $$\sum_{k=1}^{n} \binom{n}{k} k^{k-1} (n-k)^{n-k} = n^n$$ for all natural ...
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If two parallel lines meet at infinity, then what is their angle? [duplicate]

Since lines that meet at some point have an angle. And if parallel lines meet at infinity, then that what is the angle of two parallel lines that meet at infinity?
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Maximum value of the smallest number of operations to obtain configuration from original configuration

Let $n$ be a positive integer. There are $n(n+1)/2$ marks, each with a black side and a white side, arranged into an equilateral triangle, with the biggest row containing $n$ marks. Initially, each ...
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Sudoku with special properties

Sudoku is a puzzle, with the objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid (also "sudoku-blocks") contains all of ...