(2/7*3/7+(4 1/2-3 5/6)*3 1/3) : (6 1/2 : 9)=

(2/7*3/7+(4 1/2-3 5/6)*3 1/3):(6 1/2:9)=3 157/637
по действиям
4 1/2-3 5/6=1 1/2-5/6=1 3/6-5/6=1-2/6=1-1/3=2/3
2/3*3 1/3=2/3*10/3=20/9

2/7*3/7=6/49
6/49+20/9=54/441+980/441=1034/441

6 1/2:9=13/2*1/9=13/18

1034/441:13/18=1034/441*18/13=1034/49*2/13=2068/637=3 157/637