下面各题怎样简便怎样算.
6.13+28.86+13.87+1.1412×97+1.2×3071÷60-68×???????????????????8.8×(3.75-1.25)×1.25(+)÷(-)×9×41.
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解:(1)6.13+28.86+13.87+1.14,
=(6.13+13.87)+(28.86+1.14),
=20+30,
=50;
(2)12×97+1.2×30,
=12×(97+3),
=12×100,
=1200;
(3)71÷60-68×,
=(71-68)×,
=3×,
=0.05;
??
(4)8.8×(3.75-1.25)×1.25,
=[(8+0.8)×1.25]×2.5,
=[8×1.25+0.8×1.25]×2.5,
=[10+1]×2.5,
=10×2.5+1×2.5,
=25+2.5,
=27.5;
(5)(+)÷,
=(+),
=×+×,
=+,
=1;
(6)(-)×9×41,
=×9×41-×9×41,
=4×41-2×9,
=164-18,
=146.
解析分析:(1)运用加法交换律和结合律解答,(2)、(3)、(4)、(5)、(6)运用乘法分配律解答.
点评:本题主要考查学生正确运用运算定律简算的能力.