考點(diǎn):整數(shù)四則混合運(yùn)算
專題:運(yùn)算順序及法則
分析:(1)先同時(shí)運(yùn)算除法和乘法,再算加法;
(2)先算除法,再算乘法,最后算減法;
(3)根據(jù)加法交換律和結(jié)合律簡(jiǎn)算;
(4)先算小括號(hào)里面的減法,再算括號(hào)外的乘法,最后算除法;
(5)運(yùn)用乘法分配律簡(jiǎn)算;
(6)根據(jù)乘法交換律和結(jié)合律簡(jiǎn)算;
(7)先算小括號(hào)里面的乘法,再算中括號(hào)里面的除法,最后算括號(hào)外的除法.
解答:
解:(1)350÷7+24×3
=50+72
=122;
(2)618-80÷2×5
=618-40×5
=618-200
=418;
(3)243+65+(57+135)
=(243+57)+(65+135)
=300+200
=500;
(4)15×(41-17)÷30
=15×24÷30
=360÷30
=12;
(5)65×13+13×55
=13×(65+55)
=13×120
=1560;
(6)25×(9×4)×3
=(25×4)×(9×3)
=100×27
=2700;
(7)45÷[210÷(35×2)]
=45÷[210÷70]
=45÷3
=15.
點(diǎn)評(píng):本題考查了四則混合運(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)算定律進(jìn)行簡(jiǎn)便計(jì)算.