1
(3/5-2/5)÷(1/12+5/6)
=1/5÷11/12
=12/55
2
12/17÷3x4/5
=4/17x4/5
=16/85
3
[1-(1/4+3/8)]÷4
=(1-5/8)÷4
=3/8÷4
=3/32