Sometimes when I'm helping with homework, and looking for an example to practice, I find something in the workbook pages which they haven't reached yet. I find it cute when kids are nervous they'll get into trouble for having done the work before the teacher reaches that section. Of all the things to get in trouble for...!

I really, really hope they're worrying unnecessarily! I think it's better to find out early if a teacher is going to have an issue with things like that.

Hopefully his teacher is better

Your teacher worked very hard to take fun out of learning. How dare you make it interesting! :-)