(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)運用乘法分配律簡算;
(2)先算括號內的乘法,再算括號內的減法;
(3)先算括號內的,再算括號外的除法,最后算括號外的減法;
(4)運用除法的性質簡算;
(5)先算括號內的,再算括號外的除法,最后算括號外的加法.
點評:考查了小數的四則混合運算,注意運算順序和運算法則,靈活運用所學的運算律簡便計算.