11/24乘8/11+2/5除以4/7
=1/3+7/10
=31/10
3/4除以（5-6乘2/3）
=3/4*(5-4)
=3/4
(5乘3/8-5/8乘2）除以7/8
=5(3/8-2/8)除以7/8
=5/8*8/7
=5/7