1.0.76x9.9+0.076 =0.076*99+0.076=（99+1）*0.076=100*0.076=7.62.11.72-（4.3x0.4+5.6）=10+1.72-1.72+5.6=15.63.12.5x（8+0.8-0.047）=12.5*8+12.5*0.8-12.5*0.04-12.5*0.007=100+10-0.5-0.0875=109.4125