Elementary school teachers in most states, receive almost no training in anything beyond arithmetic. They do receive extensive training in teaching reading and various approaches to it, but not math. Elementary teachers are also often quite afraid of higher level math and don't really understand the concepts beyond simple multiplication and division. While they may have not only passed high school math but at least one course in college level math, they have no training in how to teach that in the classroom.
My son's third grade teacher who professed to be "excellent at math", insisted that it was okay to put a 0 as a denominator in a fraction, just as a placeholder. My son refused, it blew into a battle of wills.
Ultramarine- in CA, all 8th graders are supposed to take Algebra I. It's not uncommon to see a class of 8th grade Geometry.
