-12-5/6*3/5:(1 2/5-1.7=
1 2/5-1.7=1.4-1.7=-0.3 5/6*3/5=1/2=0.5 0.5:(-0.3)=1/2*(-10/3)=-5/3=-1 2/3 -12-(-1 2/3)=-12+1 2/3=-10 1/3