71乘40%加28乘五分之二加0.4(简算)

问题描述:

71乘40%加28乘五分之二加0.4(简算)

71*0.4+28*0.4*0.4=(71+28+1)*0.4

71×40%+28×2/5+0.4
=0.4×(71+28+1)
=0.4×100
=400