648-126-274-148
=648-148-(126+274)
=500-400
=100
8157-(104+157+597)
=8157-157-104-597
=700-104-597
=-1
365-(165+138)
=365-165-138
=300-138
=162
123+124+125+126+127
=(123+127)+(124+126)+125
=250+250+125
625
648-126-274-148
=(648-148)-(126+274)
=500-400
=100