Previous Knowledge

My college pre-calculus class had just finished the trigonometry unit and I dreaded marking the exam papers.  The students, mostly hard workers, just didn't get it.  The course spent some time reviewing the material from high school but then jumped right into the more advanced stuff.  These kids didn't have the background they needed to succeed.  No one, not even the most effective teacher in the world, can, in two hours, get students to master what they should have learned in three months.

But hey, Bloomberg is still touting his record.  Who cares if they can't read or do math?  He's graduating them all.