(3\4-4\5)*7,8+(2\3+4\7)*7\13 СРОЧНО!

(3//4-4//5)*7,8+(2//3+4//7)*7//13=(0,75-0,8)*7,8+(2//3+4//7)*(7//13)=(-0,05)*7,8+(2//3+4//7)*(7//13)=-0,05*7,8+(2//3+4//7)*(7//13)=-0,39+(2//3+4//7)*(7//13)=-0,39+26//21*(7//13)=-0,39+2//3=83//300 (~0,27) // — черта дроби