(1)2.4×5.2×1.25,
=0.3×8×5.2×1.25,
=(0.3×5.2)×(1.25×8),
=1.56×10,
=15.6;
(2)(4.8×9.9+4.8×0.1)÷1.6,
=4.8×(9.9+0.1)÷1.6,
=4.8×10÷1.6,
=48÷1.6,
=30;
(3)(3.2+18-4.04×5)÷0.2,
=(3.2+18-20.2)÷0.2,
=(21.2-20.2)÷0.2,
=1÷0.2,
=5;
(4)5.25×3.7+7.3×5.25-5.25,
=5.25×(3.7+7.3-1),
=5.25×10,
=52.5.