1)
(5/7 * 2 1/3 * 5/6 - 1) : (1 - 7/8 * 1 3/5 * 3/14) =
(5/7 * 7/3 * 5/6 - 1) : (1 - 7/8 * 8/5 * 3/14) =
(25/18 - 1) : (1 - 3/10) =
(25/18 - 1) : (7/10) =
7/18 : 7/10 = 7/18 * 10/7 =
10/18 = 5/9,
2)
2 3/5 : 6 1/15 + 1 1/14 - 1 39/73 * (5 5/7 - 5 1/16) =
13/5 : 91/15 + 15/14 - 112/73 * (40/7 - 81/16) =
13/5 * 15/91 + 15/14 - 112/73 * (640/112 - 567/112) =
3/7 + 15/14 - 112/73 * 73/112 =
6/14 + 15/14 - 1 =
21/14 - 1 = 3/2 - 1 =
1 1/2 - 1 = 1/2