解:(1)10÷0.2÷2.5,
=10÷(0.2×2.5),
=10÷0.5,
=20;
(2)64×4.5+3.6×45,
=6.4×45+3.6×45,
=(6.4+3.6)×45,
=10×45,
=450;
(3)1.25×3.2×0.8,
=(1.25×0.8)×3.2,
=1×3.2,
=3.2;
(4)14.5×102,
=14.5×(100+2),
=14.5×100+14.5×2,
=1450+29,
=1479;
(5)14.64+3.7×2.8,
=14.64+10.36,
=25;
(6)8.4÷0.21÷0.5,
=40÷0.5,
=80.
分析:(1)10÷0.2÷2.5,利用除法的性質(zhì)簡(jiǎn)算,原式變?yōu)?0÷(0.2×2.5);
(2)64×4.5+3.6×45,把64×4.5變?yōu)?.4×45,然后利用乘法的意義簡(jiǎn)算;
(3)1.25×3.2×0.8,利用乘法的交換律和結(jié)合律;(4)14.5×102,把102拆成100+2;
(5)14.64+3.7×2.8,不能簡(jiǎn)算,按運(yùn)算順序進(jìn)行計(jì)算;(6)8.4÷0.21÷0.5,按運(yùn)算順序就很簡(jiǎn)便.
點(diǎn)評(píng):此題考查學(xué)生靈活運(yùn)用運(yùn)算定律進(jìn)行簡(jiǎn)算的能力;在解答時(shí),一定先審好題再動(dòng)筆解答.