(1/8+2/9-1/4)* 5 1/7:(7/9-2/3+1/6)
1/8+2/9=25/72 25/72-1/4=7/72 (7/9-2/3+1/6)=5/18 25/72*5 1/7=1 11/14 1 11/14:5/18= 6 3/7
ответ: 6 3/7