用簡(jiǎn)便方法計(jì)算:
25×125×40×8
57×38+57×2
(20+8)×125
(163+198)+402
37×101
44×25.
解:(1)25×125×40×8,
=(25×40)×(125×8),
=1000×1000,
=1000000;
(2)57×38+57×2,
=57×(38+2),
=57×40,
=2280;
(3)(20+8)×125,
=20×125+8×125,
=2500+1000,
=3500;
(4)(163+198)+402,
=163+(198+402),
=163+600,
=763;
(5)37×101,
=37×(100+1),
=37×100+37,
=3700+37,
=3737;
(6)44×25,
=11×4×25,
=11×(4×25),
=11×100,
=1100.
分析:(1)運(yùn)用乘法交換律與結(jié)合律簡(jiǎn)算;
(2)(3)運(yùn)用乘法分配律簡(jiǎn)算;
(4)運(yùn)用加法結(jié)合律簡(jiǎn)算;
(5)把101看作100+1,運(yùn)用乘法分配律簡(jiǎn)算;
(6)把44看作11×4,運(yùn)用乘法結(jié)合律簡(jiǎn)算.
點(diǎn)評(píng):此題主要考查分?jǐn)?shù)、整數(shù)、小數(shù)的四則混合運(yùn)算的運(yùn)算順序和應(yīng)用運(yùn)算定律進(jìn)行簡(jiǎn)便計(jì)算.