(1 - 2/14) (1 + 1/3) + 6/7 = (12/14) (4/3) + 6/7 = (2/7) * (4/3) + 6/7 = 8/21 + 6/7 = (8 + 18) / 21 = 26/21 = 1 целая и 5/21.
(1 - 2/14) (1 + 1/3) + 6/7 = (12/14) (4/3) + 6/7 = (2/7) * (4/3) + 6/7 = 8/21 + 6/7 = (8 + 18) / 21 = 26/21 = 1 целая и 5/21.