-72*(1/4-5/9+7/12)/(-2)
问题描述:
-72*(1/4-5/9+7/12)/(-2)
答
=-72X(9/36-20/36+21/36)/(-2)
=-72X(-11/36+21/36)/(-2)
=-72X(10/36)/(-2)
=-72X(-5/9)
=40