a) ((5/6 - 1/3) * 3) = (5/6 - 2/6) * 3 = (3/6) * 3 = 3/2. Ответ: 3/2. b) (2 * 5/6 + 4/15) + (2 * 1/6 + 4/15) = (10/6 + 4/15) + (2/6 + 4/15) = (50/30 + 8/30) + (10/30 + 8/30) = 58/30 + 18/30 = 76/30. Ответ: 76/30. c) (3/2 * 3/2) + (1/2 * 1/2) = 9/4 + 1/4 = 10/4 = 5/2. Ответ: 5/2.