San Jose, California: Jesse Roe, a ninth-grade math teacher at a charter school here called Summit, has a peephole into the brains of each of his 38 students. He can see that a girl sitting against ...

Since its launch in 2011, Duolingo has become one of the most popular language teaching tools in the entire world, with over 500 million users learning to read and speak over 100 different languages.

The new question-of-the-week is: What has been the best math lesson you have taught and why do you think it was so good? We’ve all taught some great lessons and we’ve also all taught some pretty bad ...