3.6=0.2*1.8
2.7=0.3*9
所以3.6*2.7=0.2*18*0.3*9=1.8*18*0.3
18*0.56=1.8*5.6
所以原式=1.8*18*0.3+1.8*5.6-1.8
=1.8*(18*0.3+5.6-1)
=1.8*(5.4+5.6-1)
=18