解
1/12÷(5/6-1/3+2)
=1/12÷(5/6-2/6+2)
=1/12÷(3/6+2)
=1/12÷(1/2+2)
=1/12÷(5/2)
=1/12×(2/5)
=（1×2）/（12×5)
=1/30.