考點(diǎn):整數(shù)四則混合運(yùn)算,運(yùn)算定律與簡(jiǎn)便運(yùn)算
專(zhuān)題:運(yùn)算順序及法則,運(yùn)算定律及簡(jiǎn)算
分析:(1)把102看作100+2,運(yùn)用乘法分配律簡(jiǎn)算.
(2)運(yùn)用加法交換律與結(jié)合律簡(jiǎn)算.
(3)(6)(7)(9)運(yùn)用乘法分配律簡(jiǎn)算.
(4)運(yùn)用乘法交換律與結(jié)合律簡(jiǎn)算.
(5)運(yùn)用除法的性質(zhì)簡(jiǎn)算.
(8)把48看作4×12,運(yùn)用乘法分配律簡(jiǎn)算.
解答:
解:(1)45×102
=45×(100+2)
=45×100+45×2
=4500+90
=4590
(2)168+243+32
=(168+32)+243
=200+243
=443
(3)85×199+85
=85×(199+1)
=85×200
=17000
(4)8×9×125
=(8×125)×9
=1000×9
=9000
(5)900÷15÷6
=900÷(15×6)
=900÷90
=10
(6)35×101-35
=35×(101-1)
=35×100
=3500
(7)(25+11)×40
=25×40+11×40
=1000+440
=1440
(8)48×25
=12×4×25
=12×(4×25)
=12×100
=1200
(9)67×47+47×33
=(67+33)×47
=100×47
=4700
點(diǎn)評(píng):仔細(xì)分析數(shù)據(jù),運(yùn)用合適的方法進(jìn)行簡(jiǎn)便計(jì)算.