1) 1/7-(9/28-3/14)
2) 1 2/9-(1 5/27 - 13/18)
3) 4 2/11-(3 15/33-2 13/22)

Ответ:

Пошаговое объяснение:

1) 1/7-(9/28-3/14)=1/7-(9/28-6/28)=1/7-3/28=4/28-3/28=1/28;

2) 1 2/9-(1 5/27 - 13/18)=1 2/9 - (32/27-13/18) = 11/9-25/54=66/54-25/54 =

=41/54;

3) 4 2/11-(3 15/33-2 13/22)=4 2/11 - (3 30/66 - 2 39/66) =

= 4 2/11 - (2 96/66 - 2 39/66) = 4 2/11- 57/66 = 4 12/66 - 57/66 =

= 3 78/66-57/66 = 3 21/66 = 3 7/22.