解:(1)0.5+

+

+

,
=

+

+

+

,
=(

+

)+(1

+

),
=3+2,
=5;
(2)2

×

+6.75×75%,
=2.25×6.75+6.75×0.75,
=(2.25+0.75)×6.75,
=3×6.75,
=20.25;
(3)1.5×2004+2004×

-2004,
=1.5×2004+2004×0.5-2004,
=(1.5+0.5-1)×2004,
=1×2004,
=2004.
分析:算式一可據(jù)交換律及結(jié)合律進行巧算;算式二可據(jù)分配律進行巧算;算式三可據(jù)分配律進行巧算.
點評:進行巧算時要靈活的將式中的分數(shù)及小數(shù)進行互化.