10. Вычислите: -1 + (17/24 + 3/8) : 5/6 - 5/8

17/24 + 3/8 = 17/24 + 9/24 = 26/24 = 13/12.
(13/12) : 5/6 = (13/12) * (6/5) = 13/10.
-1 + 13/10 - 5/8 = -1 + 1.3 - 0.625 = 0.3 - 0.625 = -0.325.
В виде дроби: -1 + 13/10 - 5/8 = -40/40 + 52/40 - 25/40 = (52 - 40 - 25) / 40 = -13/40.
Ответ: -13/40