（1）1.25*6.4*7=1.25*0.8*8*7=1*56=56（2）9.9*7.8+0.78=99*0.78+0.78=0.78*（99+1）=78（3）0.77/0.55=0.11*7/0.11*5=7/5（4）7.5*1.02=7.5*（1+0.02）=7.5+7.5*0.02=7.2+0.15=7.35（5）3.7*2.8+12.5=3.7*（3-0.2...