2. Вычислите: 12 1/2 - (7 1/2 + 1 1/6)

12 1/2 = 25/2, 7 1/2 = 15/2, 1 1/6 = 7/6. 25/2 - (15/2 + 7/6) = 25/2 - 45/6 = 75/6 - 45/6 = 30/6 = 5. Ответ: 5.