You've already received excellent advice. I just wanted to add that the same processing issues creating problems in reading will create problems in a lot of areas, not just math.
Midschool has been much more difficult for my son, especially graphing and geometry. He's had the same difficulty with maps in his history class.
You'll find some teachers quite accommodating and others resistant, so I've found the best approach has been to advocate for every accommodation that is reasonable and then apply them only as needed.
