11целых 2/9+3 целых; 3целых 5/17+6целых 9/17; 4 целых 4/21+16/21
11 2/9 + 3 = 14 2/9 3 5/17 + 6 9/17 = 9 14/17 4 4/21 + 16/21 = 4 20/21