18.15-（3.5-1.75）=
问题描述：
18.15-（3.5-1.75）=
答
18.15+1.75-3.5
=20-3.5
=16.5
18.15-（3.5-1.75）=
18.15+1.75-3.5
=20-3.5
=16.5