But recently many comprehensive schools, without enough keen A-level students to justify redirecting a precious maths teacher from teaching the basics to younger students, have dropped further maths entirely.
The most important figure is, however, the one who never appears on camera: the executive producer is Oprah Winfrey, to whose movie debut this film appears to allude, not all that subtly, when Precious's teacher asks the class what their favourite colours are: her own is purple.
Precious's teacher, the aptly named Blu Rain, represents the difference we could make if we stop the judging and blaming and nurture those at the bottom of our society.
But the whole cast is so good (Lenny Kravitz is memorable in a tiny role as a male nurse's aide and Robin Thicke's wife Paula Patton is a standout as Precious' lesbian teacher) and the movie so real and harrowing that Carey's presence is not much more than a very good footnote.
That said, the easy creation and sharing of class data could shave precious minutes off teachers' schedules and leave more time for the all-important in-person interactions.
This practice has distorted and narrowed curricula, transformed many schools into de facto test prep factories, and wasted students', parents', and teachers' precious time.
To Republicans, those CEOs are 331 times more precious than the teacher who nurtures the shy child, encourages the faltering student or refuses to abandon the recalcitrant pupil.
Precious contact time with teachers, as discussed later, will increase in later steps of the study process.
Will they swallow hard as precious football teams, favorite teachers, and extra curricular activities are axed?
This focusing enables the precious time of the teacher to be used effectively.
