5/14除【6/7*(4/9+1/6）】
=5/14÷[6/7×4/9+6/7×1/6]
=5/14÷[8/21+1/7]
=5/14÷11/21
=15/22
8/9除【（2/5+1/10）*4/3】
=8/9÷[1/2*4/3]
=8/9÷2/3
=4/3