42x8+48x8用简便方法 42x8+48x8 =8*(42+48) =8*90 =720
简便计算过程方法如下 解:25x(40x8)=25x40x8=1000*8=8000
=(25*40)*8=1000*8=8000望采纳
40*(14+15)=40*29=40*(30-1)=40*30-40*1=1200-40=1160
40x1.28x40=40x(1.25+0.03)x40=40x(1.25x40+0.03x40)=40x(50+1.2)=40x50+40x1.2=2000+48=2048 谢谢,请采纳
l25十40X8=125+320=445
简便计算80X18十120X8=40x3x18+40x3x8=40x(54+24)=40x78=3120
原式=125*8*40 =1000*40 =40000
解:40*38-40*3原式=40*(38-3) =40*35 =1420
(40+384÷48)*125=(40+8)*125=40*125+8*125=500+1000=1500