Welcome! The thing that jumps out at me is that you're saying your DS is not challenged, but you're also saying he doesn't want to work at reading or maths. This must present a problem for his teachers - challenging a child does take the child's cooperation, and until a child can read and do basic maths most teachers are going to see that as the major area in which to challenge, I think. Do they do project work, e.g. does he get to research a topic and write about it? That's an important part of challenge for my own DS7 (who is similarly very knowledgeable about many things, and loves finding out more, but still finds writing quite hard). If not, maybe encouraging him to do something like this at home might be an idea?
Do you feel there's actually a problem right now, e.g. is he unhappy or bored, or do you think there might be a 2e issue he needs help with (dyslexia?) or is it just that you're looking for positive ideas of useful things to do with him?
I also notice that I'm a bit confused about where is he in reading and maths. You describe him as average in reading, but you also make it sound as though he can't really read - IME, 7yos generally "can read" (even if they need help with some words, and might fail to comprehend complex sentences). That's why my mind turned to dyslexia, although of course it's not only dyslexic children who sometimes get into reading later than you might expect from their other abilities! You also say that he loves math, but then you also say that he isn't interested in learning mathematical skills - so what do you mean when you say he loves math? Maybe that he's interested in maths stories, but not interested in drilling his times tables? If it's that we can certainly make suggestions...
