Want to solve a Rubik’s Cube? Then you have to know the numbers. Here’s the amazing math behind the legendary toy, and how to use it to solve the puzzle.

Researcher Bethany Rittle-Johnson shares strategies for how teachers can help students develop a deeper understanding of math.

On Twitter and in the comments on The Times’s website, it was clear that some readers knew immediately how to solve the problem because they had learned combinatorics, an area of math that ...