A child star from ‘Mrs. Doubtfire’ got expelled while filming. The principal framed the letter Robin Williams wrote in response.

It’s not easy to get a classroom full of wiggly, goofball five- and six-year-olds to sit through an entire day of instruction in kindergarten. Teachers have to utilize structure, routine, and just the right pacing to keep things moving. They also have to know when to dial things back and let…