what seems to be more difficult: Teaching teens or teaching large classes?

There are differents way , or strategies to teach, but depent of the people are you going to teach.
For teens you need to find out how to catch their attention,of course it has to be with topics that are interest for them.
And for large class, the most practical is to make groups in order that the teacher can assessment in a better way, so when they finish their work assignment the teacher can check the group work with difficulties.