The books have just enough math to make you feel like you know something, and Asimov's writing style is easily accessible. She will love this stuff. Gamov was trying to explain general relativity, but she will be excited that she understands a bunch of that stuff. Have her play math games with your other homeschoolers. Set is good for spatial relations.
Traverse is fun for the non-chess types.
She might be better at these games than her siblings and that might help the self-esteem. In fact, she might be able to teach you a thing or two. Bazaar is a great game for algebra skills that is available through Discovery Toys. Let her run with the science applications and she will find out what math she needs to know. There is a software package called Red Shift .