Puzzle 1: You are given nine gold coins that look identical. You are told that one of them is fake, and that this coin weighs ...

This holiday-themed brainteaser looks simple, but it's quietly tripping up adults everywhere. A math teacher walks us through ...

Label the rectangles correctly with the letters A to I. Show puzzle solution Only the four blue-shaded rectangles below intersect three other rectangles, and therefore they must be F, G, H and I. H ...

Duah: Using puzzles, both at home and in classrooms, can restore the often-forgotten truth that learning happens in ...

The rules of Sudoku dictate that every row, column and 3×3 bolded box in the completed grid must contain the digits 1 through 9 exactly once. A surprising fact emerges from these simple rules. In ...