He is not particularly good at math.
particularly
/pər-ˈti-kyə-(lər-)lē/
adverb
to an unusual degree
in particular : specifically
idiom
only a little : not very or not very much
/pər-ˈti-kyə-(lər-)lē/
to an unusual degree
in particular : specifically
only a little : not very or not very much
He is not particularly good at math.