9//56-(7//15-5//12)*(3//14+1//2)
Что за двойные палки? Дробная черта?
да
Если так, то: 9//56-(1//20*5//7)=9//56-1//28=7//56=1//8
9/56-(7/15-5/12)*(3/14+1/2)=9/56-(28/60-25/60)*(3/14+7/14)= 9/56-(3/60)*(10/14)= 9/56-(1/20)*(5/7)=9/56-5/140=9/56-1/28=9/56-2/56=7/56=1/8