（6.2-5.3）*4.2-2.8简便算法怎么算

（6.2-5.3）*4.2-2.8简便算法怎么算
（6.2-5.3）*4.2-2.8简便算法怎么算

（6.2-5.3）*4.2-2.8简便算法怎么算
（6.2-5.3）*4.2-2.8
=0.9*4.2-2.8
=0.9*7*0.6-7*0.4
=7*0.54-7*0.4
=7*(0.54-0.4)
=7*0.14
=0.84

先算括号内的得0.9然后算乘法0.9*4.2=3.78再减2.8=0.98

（6.2-5.3）*4.2-2.8=0.9*4.2-2.8=0.7*(0.9*6-4)=0.7*1.4=0.98

（6.2-5.3）*4.2-2.8
=0.9*4.2-2.8
=0.9*7*0.6-7*0.4
=7*0.54-7*0.4
=7*(0.54-0.4)
=7*0.14
=0.84