2 5/6-7 1/9=17/6-64/9=51/18-128/18=-77/18
-77/18*(-0.54)=-77/18*(-27/50)=231/100=2.31
2.31:(-0.7)=-3.3
4/23*(-5/19)=-20/437
3/23*(-3/19)=-9/437
-20/437-(-9/437)=-20/437+9/437=-11/437
-11/437*(-5.75)=-11/437*(-23/4)=11/76
-3.3:11/76=-33/10*76/11=228/10=22.8