pp - i have a 4th grader so can't answer your question but definitely email the teacher. We went to Back To School night and it seemed that all parents were just shell shocked. At the last PTA meeting the principal told everyone to contact the teacher with any questions or concerns and/or Ms. Monroe. I've had a few assignments come home that were completely puzzling and took a photo of it and forwarded it to the teacher with my question about it and heard back fairly quickly. You could also try Khan Academy for math explanations:
http://www.khanacademy.org/ I have been using youtube and wikipedia for reference a lot to help my 4th grader with homework concepts.