简便计算64.8÷[6×(2-1.8)]=64.8÷(6x0.2)=64.8÷6÷0.2=10.8÷0.2=108÷2=54
64.8÷[6×(2-1.8)]=64.8÷(6×0.2)=64.8÷1.2=54