Many of the Manga guides are good. Biochemistry is the best (http://www.amazon.com/Manga-Guide-Biochemistry-Masaharu-Takemura/dp/1593272766). The statistics one is good too but probably a little beyond most bright 10-year-olds. An interesting math book is Math Girls (http://www.amazon.com/Math-Girls-Hiroshi-Yuki/dp/0983951306) - it sort of has a plot but its more math than story. There are some good kids programming books like Python for Kids (
www.amazon.com/Python-Kids-Playful-Introduction-Programming/dp/1593274076), or Scratch Programming (www.amazon.com/Scratch-Programming-Adventure-Covers-Version/dp/1593275315).
Speaking of Scratch, it is really great if you haven't already checked that out (https://scratch.mit.edu/). Its free.