My girls (9 and 10) love Fred. The author suggests that you start at the beginning so we did, but the first ones were too simple so we jumped up to mid level and are having fun (a lot of this math is simple as well but mixed in with some items that are new to my girls). We have run across one item in the lower level books that kind of surprised me - Fred finds out that animals are put to death in animal shelters if no one adopts them. My girls didn't know that so we ended up with a big discussion about that topic. It might be a bit much if you have a younger child who is sensitive.
