（1）2.5*32*0.125=（2.5*4）*（8*0.125）=10*1=10（2）3.5-7+6.5=3.5+6.5-7=3（3）1.2×2.5+0.8×2.5 =2.5(1.2+0.8)=25（4）8.9×1.25-0.9×1.25 =1.25(8.9-0.9)=10
