1.6×(12.5-1.25-0.125)=1.6×12.5-1.6×1.25-1.6×0.125=0.4×4×12.5-0.4×4×1.25-0.4×4×0.125=0.4×（4×12.5）-0.4×（4×1.25）-0.4×（4×0.125）=0.4×50-0.4×5-0.4×0.5=20-2-0.2=18-0.2=17.8
