1)2-3 целых 1/7*(2-1 целая 9/11):8/21 2) 2 целых 1/3+4 целых 1/10:(2 целых 7/15-5/12)*5/6 3)4 целых 5/12-1 целая 1/2:(2

1) 2 - 3 1/7 * (2 - 1 9/11) : 8/21 = 2 - 22/7 * (22/11 - 20/11) : 8/21 = 2 - 22/7 * 2/11 * 21/8 =

= 2 - 44/77 * 21/8 = 2 - 924/616 = 1232/616 - 924/616 = 308/616 = 77/154 = 1/2; 

2) 2 1/3 + 4 1/10 : (2 7/15 - 5/12) * 5/6 = 7/3 + 41/10 : (37/15 - 5/12) * 5/6 = 7/3 + 41/10 :

: (148/60 - 25/60) * 5/6 = 7/3 + 41/10 : 123/60 * 5/6 = 7/3 + 41/10 * 60/123 * 5/6 = 7/3 + 

+ 6/3 * 5/6 = 7/3 + 5/3 = 12/3 = 4;

3) 4 5/12 - 1 1/2 : (2 1/6 + 8/15) * 1 4/5 = 53/12 - 3/2 : (13/6 + 8/15) * 9/5 = 53/12 - 3/2 : 

: (65/30 + 16/30) * 9/5 = 53/12 - 3/2 : 81/30 * 9/5 = 53/12 - 3/2 * 30/81 * 9/5 = 53/12 -

- 15/27 * 9/5 = 53/12 - 1 = 53/12 - 12/12 = 41/12 = 3 5/12.