6.48×(0.9÷0.6)=6.48×1.5=6.48×(1+0.5)=6.48+6.48×0.5=6.48+3.24=9.72
6.48÷[(3.3-2.7)×0.9]=6.48÷0.6÷0.9=10.8÷0.9=12
6.48÷0.9÷(3.3-2.7)=7.2/0.6=1.2
6.48÷[(3×1.1-3×0.9)×0.9 ]=6.48÷3÷0.2÷0.9=12