If you are thinking in terms of - is he doing better one on one than he could do in the school, that is a possibility. When I think of compensating, I think of a child with a learning disorder/difference who is using other clues/parts of the brain to get by. They are struggling even though they might still be getting ok grades, when stressed this would show up more.
What additional testing did the psych suggest? Could you have something similar done through the school? I would consider the additional testing to get a handle on what if any accomodation he might need in the classroom to really do his best(and enjoy math instead of sort of be ok with it)
I am not sure of the 4th grade curriculum; our school does 'investigations' so it goes back and forth a bit, but in 3rd it's some geometry (planes and solids, various terms, etc) Measurement, no formulas other than perimeter, and not even in a formulaic way right now. Beginning multiplication concepts, some practice on the lower numbers.
