New posts in Recreational Mathematics

Difficult coin weighing puzzle: 14 coins, 1 fake (heavier or lighter), 3 pre-determined weighings

Olympiads Number Theory Problem: Show that there are no positive $a,b,c\in\Bbb Z$ such that $\frac{a^2+b^2+c^2}{3(ab+bc+ca)}\in\Bbb Z$

Intuition behind sums of sums of whole numbers

Rotating a quarter circle -- how long has a point traveled.

Struggling to Understand Algorithm for Displaying Polynomial Matings with Julia Sets

What are some puzzles that are solved by using invariants?

What happens when we (incorrectly) make improper fractions proper again?

Is there a smooth, preferably analytic function that grows faster than any function in the sequence $e^x, e^{e^x}, e^{e^{e^x}}...$

What is the size of each side of the square?

Erase every other number from $1, 2, 3, ... 2000$ until only one number left