Вычислите: 1) (-3/14 - 8/21) : 20/21; 3) (-4 1/12 +

1) (-3/14 - 8/21) : 20/21=(-9-16)/42 * 21/20=-25/42 * 21/20=-5/2 * 1/4=-5/8;
2) 3/8 : (-5/8) - (-2 1/4) : (-1 4/11)=3/8 * (-8/5) + 9/4 * (-11/15)=3/1 * (-1/5)+3/4 * (-11/5)=
-3/5 - 33/20=(-12-33)/20=-45/20=-9/4=-2 1/4;
3) (-4 1/12 + 3 9/10) : 3 3/10=(-1 1/12 + 9/10) * 10/33=(-13/12 + 9/10) * 10/33=
(-65+54)/60 * 10/33=-11/6 * 1/33=-1/6 * 1/3=-1/18;
4) (11/14 - 5/6) : (11/14 - 3/4)=(33-35)/42 : (22-21)/28=-1/21 * 28/1=-1/3 * 4/1=-4/3=
-1 1/3.