Пошаговое объяснение:

№1

11/66 = 1/6 = 2/12

11/66 = 1/6 = 3/18

11/66 = 1/6 = 10/60

№2

1717/1818 + 55/99 - 22/33 = 17/18 + 5/9 - 2/3 =

17/18 + 10/18 - 12/18 = 15/18 = 5/6