I think perhaps you are approaching the wrong audience. My very mathy kid who also reads far above grade level, does not struggle with math word problems. His only problems come when the wording of the question is vague or the expected answer is unclear, as is often the case in his mediocre, multiple-choice math tests at school.
Example- recent word problem from his book (dates modified because I do not remember the specifics).
John went to the park 7 days ago. If today is Sunday, June 12th, what day did John go to the park?
a) Sunday June 19th
b) Monday June 6th
c) Wednesday, June 1st
d) Saturday June 11th
Um... well the choice of Sunday, June 5th wasn't available. So we were left to figure that 7 days ago must have been inclusive of the current day, meaning that Monday, June 6th was the only possible answer.
