用简便方法计算. 98×10558×69+31×58125×43×869×40-44×404388-687-313(48×25)×8.
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解:(1)98×105,
=98×(100+5),
=98×100+98×5,
=9800+490,
=10290;
(2)58×69+31×58,
=58×(69+31),
=58×100,
=5800;
(3)125×43×8,
=(125×8)×43,
=1000×43,
=43000;
(4)69×40-44×40,
=40×(69-44),
=40×25,
=1000;
(5)4388-687-313,
=4388-(687+313),
=4388-1000,
=3388;
(6)(48×25)×8,
=48×(25×8),
=48×200,
=9600.
解析分析:(1)(2)(4)运用乘法的分配律计算,(3)运用乘法的交换律、结合律计算,(5)从一个数里减去两个数等于减去这两个数的和,(6)运用乘法结合律简算.
点评:考查学生对运算定律的运用能力.