用简便方法计算下面各题. 2.7×4.36+2.7×4.64+2.74.7×62××.
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解:(1)2.7×4.36+2.7×4.64+2.7,
=2.7×(4.36+4.64+1),
=2.7×10,
=27;
(2)4.7×+5.3÷1-6.5,
=4.7×+5.3×-6.5,
=×(4.7+5.3)-6.5,
=6.5,
=7.5-6.5,
=1;
(3)62××,
=×
=,
=,
=207;
(4)2x÷=40,
????? 2x×4=40,
???????? 8x=40,
????? 8x÷8=40÷8,
????????? x=5;
解析分析:(1)、(2)运用乘法的分配律进行计算即可.(3)把带分数化成假分数再运用分数乘法的计算法则进行计算即可.(4)运用等式的性质进行解答即可.
点评:本题考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算,同时考查了方程的解答情况.