Dennis, as a parent tutoring my own children through various classes, I can only say that we've had to "grin and bear" this kind of thing. Recall we have the teacher who marked my daughter down 25% for incorrectly stapling an assignment.
I am currently working with my daughter on surface area and volumes of cylinders and irregular solids. *I* know that expressing the answer with pi is more exact than rounding pi in all the calculations, which of course compounds rounding differences, but my daughter has to write the answer both ways b/c she will be penalized if she doesn't write it the right way. To make matters more confusing, the answers to the odd problems in the back sometimes express the answer in terms of pi, but others have a rounded decimal answer, albeit with the "approximately" symbol in front. So to be certain she doesn't get marked down, she does both. This is the way homework goes every week - I have to work to undo the formulaic thinking she's been taught, help her to understand why she'd doing what she's doing, and then we have to "package" it very carefully to be sure the teacher does not penalize her for any creativity or off the page thinking.
I just keep showing her why she's doing things, and we're very clear on when she's jumping through hoops for the grade vs. doing something the way it makes sense to her. I try to keep her motivated to use her reasoning, in spite of these kinds of grading tactics that encourage a kid to NOT reason but to follow rules to the nit. It's so hard on kids who care about their grades to be penalized like this, and turns them off of math. I was blown away how on a quiz she was required to draw a 110 degree angle with a protractor, she was within a couple degrees, and was marked wrong.
Is there anything so "sacred" about these answers, in contrast to the ones she gave?
Does the solution of x = 3 really NEED to be expressed as x = 3.000?