1.75×53.8-0.537×75-53.7
=1.75×53.8-53.7×0.75-53.7
=1.75×53.8-53.7×（0.75+1）
=1.75×53.8-53.7×1.75
=1.75×（53.8-53.7）
=1.75×0.1
=0.175