如题所述
第1个回答 2016-11-15
您好，解法为：
原式
=259+（800+200）······································································加法结合律
=259+1000
=1259
原式
=259+（800+200）······································································加法结合律
=259+1000
=1259
第2个回答 2016-11-15
脱试计算本回答被提问者采纳
