Try this:"a large percentage" ... and you're asking me for calculations. hahaha that's funny!
How's this:
overpaid teachers salaries - "large percentage" of multiple children = unions are pissed off because they aren't able to hold kids hostage as long as they thought they could
The number of kids in a class x the Ford payoff - teachers daily salary.
I understand that this would be too hard for you, but still I want to give you the chance.