用简便方法计算,写出简算过程
(1)2.5×3.2×1.25?????????
(2)4.05-(2.05+)
(3)5.39++4.61+
(4)0.588×+4×9.412+×0.588.
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解:(1)2.5×3.2×1.25,
=(2.5×0.4)×(8×1.25),
=1×10,
=10;
(2)4.05-(2.05+),
=4.05-2.05-,
=2-,
=1;
(3)5.39++4.61+,
=(5.39+4.61)+(1+),
=10+2,
=12;
(4)0.588×+4×9.412+×0.588,
=0.588×(1+2)+4×9.412,
=0.588×4+4×9.412,
=4×(0.588+9.412),
=4×10,
=40.
解析分析:(1)把3.2看作0.4×8,运用乘法结合律进行简算;(2)运用减法的性质简算;(3)运用加法的交换律和结合律进行简算;(4)运用乘法分配律进行简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.