12.7-（3.7+0.84）=(12.7-3.7)-0.84=9-0.84=8.16
36.54-1.76-4.54=(36.54-4.54)-1.76=32-1.76=30.24
0.25×0.73×4=(0.25*4)*0.73=1*0.73=0.73
7.6×0.8+0.2×7.6=7.6*(0.8+0.2)=7.6*1=7.6
0.85×199=0.85*(200-1)=0.85*200-0.85*1=170-0.85=169.15
12.5×0.96×0.8=(12.5*0.8)*0.96=10*0.96=9.6