(2целых 8/35-1целая 13/35)+(3целых 20/49-2целых 27/49
(2 8/35 - 1 13/35) + (3 20/49 - 2 27/49) = 30/35 + 42/49 = 6/7+ 6/7 = 12/7 = 1 5/7;