I like Val's approach:
"I think that one of my parental duties is to teach my kids that sometimes stuff is wrong, even stuff in school. I took this approach with EM with my eldest, and I do the same with my youngest when she gets bogus homework questions. Unless you leave the school or negotiate independent study, this is a way around the bad curriculum."
The new math programs were slapped together quickly to comply with new standards. I found typos, grammatical errors, and flat out wrong math problems in my son's math program. We switched schools because of it.