1) (1 3/28-25/42-5/14):
2 2/13+11/13:1 7/26= 1
-25/42-5/14=-25/42-15/42=
-40/42= -20/21
1 3/28-20/21=31/28-20/21=
186/168-160/168=26/168=
13/84
13/84:2 2/13=13/84×28/13=1/3
11/13: 1 7/26=11/13×26/33=2/3
1/3+2/3=3/3=1
2) (2 1/12:2 1/2)+(1 9/28-16/35)*2 6/11-11/30=
2 1/12:2 1/2=25/12×2/5=5/6
1 9/28-16/35=37/28-16/35=
185/140-64/140=121/140
121/140×2 6/11=
121/140×28/11=11/5
5/6+11/5-11/30=
25/30+66/30-11/30=80/30=2 20/30= 2 2/3