(-2,5-1(5/6))÷1(4/9)-3(5/9)×(-2(1/4))=5
1) -2,5-1(5/6)=-(25/10)-(11/6)=-(25×3+11×5)/30=-(75+55)/30=-(130/30)=-13/3
2) -(13/3)÷1(4/9)=-(13/3)÷(13/9)=-(13×3×3)/(13×3)=-3/1=-3
3) 3(5/9)×(-(2(1/4))=-(32/9)×(9/4)=-(8×4×9)/(9×4)=-8/1=-8
4) -3-(-8)=-3+8=5
((3/4-1(7/8))÷(3/4)+3(1/9)×(3/7)=-1/6
1) (3/4)-1(7/8)=(3/4)-(15/8)=(3×2-15)/8=(6-15)/8=-9/8
2) -(9/8)÷(3/4)=-(3×3×4)/(4×2×3)=-3/2
3) 3(1/9)×(3/7)=(28/9)×(3/7)=(7×4×3)/(3×3×7)=4/3
4) (-3/2)+(4/3)=(-3×3+4×2)/6=(-9+8)/6=-1/6