考點(diǎn):運(yùn)算定律與簡(jiǎn)便運(yùn)算
專題:運(yùn)算順序及法則
分析:①102=100+2,然后根據(jù)乘法分配律,計(jì)算即可;
②根據(jù)乘法分配律,展開,計(jì)算即可;
③45=9×5,根據(jù)除法的性質(zhì),計(jì)算即可;
④24=3×8,然后乘法結(jié)合律,計(jì)算即可;
⑤9=10-1,99=100-1,999=1000-1,9999=10000-1,然后根據(jù)加法交換律和結(jié)合律,計(jì)算即可;
⑥888=222×4,則888×211=222×844,然后根據(jù)乘法分配律,提取222,計(jì)算即可.
解答:
解:①102×35
=(100+2)×35
=100×35+2×35
=3500+70
=3570
②(25+20)×4
=25×4+20×4
=100+80
=180
③720÷45
=720÷(9×5)
=720÷9÷5
=80÷5
=16
④24×125
=(3×8)×125
=3×(8×125)
=3×1000
=3000
⑤9+99+999+9999
=(10-1)+(100-1)+(1000-1)+(10000-1)
=10+100+1000+10000-(1+1+1+1)
=11110-4
=11106
⑥156×222+888×211
=156×222+(222×4)×211
=156×222+222×(4×211)
=156×222+222×844
=222×(156+844)
=222×1000
=222000
點(diǎn)評(píng):考查了運(yùn)算定律與簡(jiǎn)便運(yùn)算,四則混合運(yùn)算.注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算律簡(jiǎn)便計(jì)算.