把括号里面分出个4来比较简单。具体如下
(12+24+80)×25
=116×25
=(100+10+4+2)×25
=100×25+10×25+4×25+2×25
=2500+250+100+50
=2750+150
=2900
与其费尽心思想简便方法,
不如动手列个算式方便一点。
(12+24+80)×25
=12×25+24×25+80×25
=3×(4×25)+6×(4×25)+20×(4×25)
=3×100+6×100+20×100
=300+600+2000
=2900
(12+24+80)×25=(12+24+80)×5×5=(12×5+24×5+80×5)×5=(60+120+400)×5=580×5=2900