New posts in recreational-mathematics

How to reach 1000 reputation?

The Farmyard Problem: Minimize the amount of ditch-digging needed to locate a straight pipe under a square piece of land

Puzzle: Cut regular tetrahedron into distinct-sized regular tetrahedra?

Making numbers from 2, 0, 1, 7. Also: are the the iterative factorials and square roots, starting from any $s>2$, dense in $[1,\infty)$?

Classifying all numbers $n$ with the property that if $p$ is a prime, then $p \mid n \iff p-1 \mid n$

Is Conway's "Look and Say Sequence" strictly increasing?

Arbitrarily long palindromes in two consecutive number bases

How do people create difficult, recreational problems (e.g. like those found in competitions such as the IMO)?

What is the probability that a solitaire game be winnable?

Puzzle: Cracking the safe [duplicate]

Areas of math that can be "gamified"?

Find all bijections $\,\,f:[0,1]\rightarrow[0,1],\,$ which satisfy $\,\,f\big(2x-f(x)\big)=x$.

Interview puzzle with a deck of cards, some cards upside-down

Is $3 \ge 1$ or is it just $3 > 1$?

Wrong answers to simple trigonometry questions

4 crystal balls and a 10,000 story building

Function that maps the "pureness" of a rational number?

When the roulette has hit 5 reds why shouldn't I bet to black?

Approximate $\sqrt{e}$ by hand

Beautiful, simple proofs worthy of writing on this beautiful glass door [closed]