1.2.3*3.14-1.2*3.14+8.9*3.14= (2.3-1.2+8.9)*3.14=10*3.14=31.42.2.56*15+14.4*0.5-0.3*150 = 2.56*15+14.4*0.5-0.3*150 = 2.56*15+1.44*5-3*15 = 2.56*15+0.48*15-3*15 = (2.56+0.48-3)*15 = (3.04-3)*15 =0.04*1...是2.56*15+14.4*1.5-0.3*1502.56*15+14.4*1.5-0.3*150 = 2.56*15+1.44*15-3*15 = (2.56+1.44-3)*15 = (4-3)*15 =1*15=15