666×333+778×999
=(222×3)×333+778×999
=222×(3×333)+778×999
=222×999+778×999
=(222+778)×999
=1000×999
=999000
333x(666+778x3)=999x(222+778)=999+1000=999000
666x333+778x999
=(222x3)x333+778x999
=222x(3x333)+778x999
=222x999+778x999
=999x(222+778)
=999x1000
=999000