2) 1 2/3 + 6 4/15 + 8 17/45 = 1 30/45 + 6 12/45 + 8 17/45 = 7 42/45 + 8 17/45= 15 59/45 (16 14/45)
4) сразу ответ 5 21/60 + 20 16/60 + 12 11/60 = 25 37/60 + 12 11/60 = 37 48/60(12/15)
6) 31 42/54 + 4 22/54 + 35 43/54 = 35 64/54+35 43/54=70 107/54( 71 53/54)