9.9乘7.27=（10-0.1）×7.27=72.7-0.727=71.973 ( 3.2+0.128)除以0.8=3.2÷0.8+0.128÷0.8=4+0.16=4.16
9.9乘7.27=(10-0.1)乘7.27=72.7-0.727=71.973( 3.2+0.128)除0.8=3.2除0.8+0.128除0.8=4+1.6=5.6
直接按计算器~
