(12)0.4×(3.2-0.8)÷0.15,
=0.4×2.4÷0.15,
=0.96÷0.15,
=6.4;
(13)5.7+1.9×0.2÷7.6,
=5.7+0.38÷7.6,
=5.7+0.05,
=5.75;
(14)32.4×6.3+32.4×3.7,
=32.4×(6.3+3.7),
=32.4×10,
=324;
(15)18.2-10.6×(0.9-0.75),
=18.2-10.6×0.15,
=18.2-1.59,
=16.61;
(16)0.25×3.85×40,
=0.25×40×3.85,
=10×3.85,
=38.5;
(17)1.46×3.5+3.5×4.54,
=3.5×(1.46+4.54),
=3.5×6,
=21.