Hi there ConfusedParent,
I'm new here: what do YSP and SBV mean?
I'm a confused parent too, as I'm just beginning to grapple with my the education of my kids (oldest is 7).
I think you hit the nail on the head when you said that reading is more of a struggle. As a natural thing, people put the most effort into subjects that are most interesting to them. And if mathematics is very, very easy and very fascinating for your child, he may not be enthusiastic about putting extra effort in somewhere else. Even thought reading may come more easily to him than most other kids, it's still a lot harder *for him* than maths. So he would have a natural preference for maths.
Sometimes we have our kids work at things that *aren't* easy for them. Doing this seems to teach them what can come of a little hard work. You should see them grin when they realize that they can do something that they thought was outside their reach! We do this as a way to help develop study and habits they'll need later on.