1.12.5×4.8÷1.5÷5 =12.5×1.6×3÷(0.5×3×5)=12.5÷2.5×1.6×3÷3=5×1.6=8;2.(9.45+9.9)÷0.9=9.45÷0.9+9.9÷0.9=10.5+11=21.5;3.13.75+45÷1.8×25 =13.75+5×25×9÷1.8=13.75+25×25=13.75+625=638.75如...