We checked these out as previewers, before they were released. My kiddo was in 3rd, but in an accelerated program (so doing 4th grade stuff). He took the pretest and already knew pretty much all of it, so I'd say that you might want to do pretests if those are available to see what level your kiddo is at. Because he knew most of the material, he wasn't so interested in testing out the problems, which looked to me to be pretty challenging. He liked the comic book format, though, and read through the unit in one sitting.
