(1)99×6.25+6.25
(2)(5.6×0.3-0.68)÷0.25×4
(3)6.9-(0.6+4.5)÷1.7
(4)7.2÷1.25÷0.8
(5)(25.5+17.25)÷0.25+0.75
(6)2.63×2.3+2.3+6.37×2.3.
解:(1)99×6.25+6.25,
=(99+1)×6.25,
=100×6.25,
=625;
(2)(5.6×0.3-0.68)÷0.25×4,
=(1.68-0.68)÷0.25×4,
=1÷0.25×4,
=4×4,
=16;
(3)6.9-(0.6+4.5)÷1.7,
=6.9-5.1÷1.7,
=6.9-3,
=3.9;
(4)7.2÷1.25÷0.8,
=7.2÷(1.25×0.8),
=7.2÷1,
=7.2;
(5)(25.5+17.25)÷0.25+0.75,
=42.75÷0.25+0.75,
=171+0.75,
=171.75;
(6)2.63×2.3+2.3+6.37×2.3,
=(2.63+1+6.37)×2.3,
=10×2.3,
=23.
分析:(1)(6)運(yùn)用乘法分配律簡算;
(2)先算括號(hào)內(nèi)的乘法,再算括號(hào)內(nèi)的減法;
(3)先算括號(hào)內(nèi)的,再算括號(hào)外的除法,最后算括號(hào)外的減法;
(4)運(yùn)用除法的性質(zhì)簡算;
(5)先算括號(hào)內(nèi)的,再算括號(hào)外的除法,最后算括號(hào)外的加法.
點(diǎn)評(píng):考查了小數(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.