Hannah Cairo found herself stuck on a problem that wouldn’t leave her mind. It wasn’t a regular homework assignment—it was a ...

A few weeks ago, a father posted a page from his son's supposed common-core math assignment on Facebook, claiming that despite his own degree in engineering, he could not solve the problem.

Three school math problems have thousands of people on Facebook and Reddit talking. The reason? Even though the students' answers appear to be totally correct, they were still marked wrong. Here's ...