Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

After Terri Ackerman went missing, police searched around the home and neighborhoods with drones and dogs, followed up on ...

Stage 5: Justify thinking. A vital habit that many students need to solidify is recontextualizing after they solve ...

This brain teaser is designed to gauge your logical and analytical thinking abilities, but it also tests your ability to ...

The latest observations were made on November 5 by researcher Qicheng Zhang of the Lowell Observatory in Arizona ...