下面各题怎样简便就怎样计算
102×25-4181379+450÷18×400.4+2.6÷(4.7-3.4)(-)+1÷(+)×77×(-)
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解:(1)102×25-418
=(100+2)×25-418,
=100×25+2×25-418,
=2500+50-418,
=2550-418,
=2132;
(2)1379+450÷18×40,
=1379+450÷9÷2×40,
=1379+25×40,
=1379+1000,
=2379;
(3)0.4+2.6÷(4.7-3.4),
=0.4+2.6÷1.3,
=0.4+2,
=2.4;
(4)(-)+,
=×2+,
=+,
=1;
(5)1÷(+)×,
=1÷×,
=×,
=;
(6)77×(-)
=77×-77×,
=12.6-9,
=3.6.
解析分析:(1)可将式中102拆分100+2后根据乘法分配律计算;
(2)可根据除法的性质将450÷18变为450÷9÷2进行计算;
(3)、(4)、(5)根据四则混合运算的运算顺序计算即可,先算乘除,再算加减,有括号的要先算括号里面的;
(6)可根据乘法分配律计算.
点评:完成本题要注意分析式中数据,然后运用合适的方法计算.