简便计算3.06x1.5-2.08=3x1.5+0.06x1.5-2.08=4.5+0.09-2.08=4.59-2.08=2.51
原式=3x1.5+0.06x1.5-2.08=4.5+0.09-2.08=4.59-2.08=2.51