[25+20]×4
=25×4+20×4
=100+80
=180谢谢，那13×99+13 106×25 怎么用简便方法做呢？[都要列综合] 快噢。急13×99+13=13×99+13×1=13×（99+1）=13×100=1300106×25=（100+4+2）×25=100×25+4×25+2×25=2500+100+50=2650