1017. Выполните действия:

  а) 18/19 − 7/19 + 3/19 = 14/19;

  б) 2/7 + 4/7 − 5/7 = 1/7;

  в) 9/11 − 3/11 − 2/11 = 4/11;

  г) 5/12 + 3/12 + 3/12 = 11/12;

  д) 11/15 − (3/15 + 7/15) = 11/15 − 10/15 = 1/15;

  е) 13/16 − (13/16 − 3/16) = 13/16 − 10/16 = 3/16.