(7/24)×(3/4)+(7/24)÷4
=(7/24)×(3/4)+(7/24)×(1/4)
=(7/24)×(3/4+1/4)
=(7/24)×1
=7/24
(7/8)×8÷(7/8)×8
=(7/8)÷(7/8)×8×8
=1×8×8
=64
(7/36)÷(11/12)÷(5/33)
=(7/36)×(12/11)×(33/5)
=(7/36)×(12/11×33/5)
=(7/36)×(36/5)
=7/5
(1-7/9÷7/8)×(1-5/6)
=(1-8/9)×(1/6)
=(1/9)×(1/6)
=1/54