用你喜欢的方法计算下面各题
÷〔×(1-)〕(-)×(20-1.25×0.8)÷0.196.88×7.8+3.2×6.88-6.885.58-+5.42-325×0.36+6.75×36.
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解:(1)÷[×(1-)],
=÷[×],
=÷,
=×6,
=;
(2)(-)×,
=×-×,
=-,
=;
(3)(20-1.25×0.8)÷0.19,
=(20-1)÷0.19,
=19÷0.19,
=100;
(4)6.88×7.8+3.2×6.88-6.88,
=6.88×(7.8+3.2-1),
=6.88×10,
=68.8;
(5)5.58-+5.42-,
=(5.58+5.42)-(+),
=11-1,
=10;
(6)325×0.36+6.75×36,
=3.25×36+6.75×36,
=(3.25+6.75)×36,
=10×36,
=360.
解析分析:(1)先算小括号内的,再算中括号内的,最后算括号外的;(2)(4)运用乘法分配律简算;(3)先算括号内的乘法,再算括号内的减法,最后算括号外的除法;(5)运用加法交换律与结合律简算;(6)根据数字特点,把原式变为3.25×36+6.75×36,运用乘法分配律简算.
点评:此题主要考查分数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.