The most important goal for third graders in math is to learn their multiplication and division facts. It would be smart to purchase flash cards in multiplication the first week of school. Anytime your child is bored, they can practic. Having taught fourth and fifth grade as well, I can't emphasize enough the importance of knowing these quickly.

Math books can go home. There is extra practice and trouble shooting in the back

If a concept gives you or your child trouble, visit AAAmath.com. Go to grade three and there is a lesson and timed practice for just about every concept.