((49/8)*(9/7)-(39/14)*(21/13))*(8/5)
(63/8-9/2)*8/5
63/5-36/5
27/5 или 5.4
68+12=80
68+56=124
12+56=68
68-12=56
68-56=12
56-12=48
68+12+56=136
68-12+56=112
68+12-56=24
68-12-56=0