0.47×0.5×0.80.47×(0.5×0.8)0.47×0.40.188
0.47X0.5Ⅹ0.8=0.47X(0.5X0.8)=0.47X0.4=0.188
先把0.5✘0.8
o.47×(0.5×0.8)=0.47×0.4=0.188