题目内容
计算,能简便计算的要简便计算. (1)(9+92+93)×0.01 | (2)13.5×[1.5×(1.07+1.93)] | (3) |
(4)(333+667)÷[63×()] | (5)++++ | (5)1998÷1998. |
解:(1)(9+92+93)×0.01
=[9+9×(9+9×9)]×0.01,
=[9+9×(9+81)]×0.01,
=[9+9×90]×0.01,
=[9+810]×0.01,
=819×0.01,
=8.19;
(2)13.5×[1.5×(1.07+1.93)]
=13.5×[1.5×3],
=13.5×4.5,
=60.75;
(3)
=+×(-),
=+×,
=+,
=+,
=;
(4)(333+667)÷[63×()]
=1000÷[63×-63×],
=1000÷[36-28],
=1000÷8,
=125;
(5)++++
=++++,
=-+-+-+-+-,
=-,
=;
(5)1998÷1998,
=1998÷,
=1998×,
=.
分析:算式(1)括号中的可根据乘法分配律计算;
算式(2)(3)根据四则混合运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号的里面的;
算式(4)中括号内的可根据乘法分配律计算;
算式(5)可根据=-进行计算;
算式(6)可将带分数化为假分数后通过约分计算.
点评:完成本题要认真分析式中数的居特点及内在联系,然后运用合适的方法进行计算.
=[9+9×(9+9×9)]×0.01,
=[9+9×(9+81)]×0.01,
=[9+9×90]×0.01,
=[9+810]×0.01,
=819×0.01,
=8.19;
(2)13.5×[1.5×(1.07+1.93)]
=13.5×[1.5×3],
=13.5×4.5,
=60.75;
(3)
=+×(-),
=+×,
=+,
=+,
=;
(4)(333+667)÷[63×()]
=1000÷[63×-63×],
=1000÷[36-28],
=1000÷8,
=125;
(5)++++
=++++,
=-+-+-+-+-,
=-,
=;
(5)1998÷1998,
=1998÷,
=1998×,
=.
分析:算式(1)括号中的可根据乘法分配律计算;
算式(2)(3)根据四则混合运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号的里面的;
算式(4)中括号内的可根据乘法分配律计算;
算式(5)可根据=-进行计算;
算式(6)可将带分数化为假分数后通过约分计算.
点评:完成本题要认真分析式中数的居特点及内在联系,然后运用合适的方法进行计算.
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