Share 'Teens, and Unschooling'

I've been unschooling my boys for over a year now, and I'm having  concerns that I'm missing something in their education in the areas of Math and English. They've never had much of an interest in writing, even if I asked them to write about something they loved using the computer they wouldn't have an interest in writing about it. Is this something that I should just let go, or should I be encou…