简便运算的题..
问题描述：
简便运算的题..
14除[(十分之九-三分之二)*15]
[十分之九-(1-四分之三)]*七分之五
SOS...
答
14/[(9/10-2/3)*15]
=14/(9*15/10-2*15/3)
=14/(27/2-20/2)
=14/(7/2)
=14*2/7
=4
[9/10-(1-3/4)]*5/7
=(9/10-1/4)*5/7
=9*5/(10*7)-5/(4*7)
=9/14-5/28
=18/28-5/28
=13/28