Most or Most of..?

Most of older teachers and some younger teachers are not technology literate.

Today I'm going to give you a task!

Take a look at these sentences and try to identify any words or phrases that follow most of.

Then compose a rule that explains why "Most of older teachers.." is incorrect. Share your rule with a teacher or a friend!

Then think about why "some younger teachers" is correct. Does the rule for most/most of also apply to some/some of?