解:(1)6.8×

+0.32×3.2,
=6.8×0.32+0.32×3.2,
=(6.8+3.2)×0.32,
=10×0.32,
=3.2;
(2)

÷

+3.75×

,
=

×

+

×

,
=

×(

+

),
=

×

,
=9;
(3)

×0.3÷

×0.3
=

÷

×0.3×0.3,
=1×0.3×0.3,
=0.09;
(4)

÷[(

-

)×

],
=

÷[

×

],
=

÷

,
=3.
分析:(1)把分?jǐn)?shù)化為小數(shù),運(yùn)用乘法分配律簡算;
(2)把小數(shù)化為分?jǐn)?shù),運(yùn)用乘法分配律簡算;
(3)調(diào)整一下運(yùn)算順序,原式變?yōu)?img class='latex' src='http://thumb.zyjl.cn/pic5/latex/168.png' />÷

×0.3×0.3,從左往右依次運(yùn)算;
(4)先算小括號(hào)內(nèi)的,再算中括號(hào)內(nèi)的,最后算括號(hào)外的.
點(diǎn)評(píng):考查了分?jǐn)?shù)的四則混合運(yùn)算,注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算律簡便計(jì)算.