I have bought this series of books for my sons to keep them learning through the summer months. We set aside an hour twice a week to do some "homework" from these books and they actually look forward to it. I buy the next grade level so that they will be challenged and ready for school in the fall. I am actually at Overstock ordering the books for this summer today because my 6 year old reminded that I had not bought them yet! Like I said, they really like them! They do a couple of pages each time and seem to like the format, maybe because it is different from what they have a school, but still keeps up with what they should be working on! Bright and colorful pages make the "homework" inviting.