844+129+156+71 =(844+156)+(129+71) =1000+200 =1200 351-68-132 =351-(68+132) =351-200 =151 101×48 =(100+1)×48 =100×48+48 =4848 45×(100-8) =45×100-45×8 =4500-360 =4140