1/9÷1/6÷3/5
=1/9×6×5/3
=10/9
=1又1/9

2/5÷4/7×5/7
=2/5×7/4×5/7
=1/2

(5/12+1/27）×27+5/8
=5/12×27+1/27×27+5/8
=45/4+1+5/8
=12又7/8