题目内容
列式计算,能简算的简算
(1)2010-4848÷9.6×2.4
(2)(-×)÷
(3)×[-(-)]
(4)(++)×12+
(5)已知18+[×1.25+(+________×12]÷0.125=86,求出横线上应填的数.
解:(1)2010-4848÷9.6×2.4,
=2010-505×2.4,
=2010-1212,
=798;
(2)(-×)÷,
=(),
=,
=2.25;
(3)×[-(-)],
=×[-],
=×,
=0.5;
(4)(++)×12+,
=×12×12×12,
=8+5+(),
=13+1,
=14;
(5)设要求的数是x,
18+[×1.25+(+x×12)]÷0.125=86,
18+[×1.25++12x]÷0.125=86,
18+[1+12x]÷0.125=86,
18+8+96x=86,
26+96x-26=86-26,
96x÷96=60÷96,
x=0.625.
答:要求的数是0.625,
故答案为:798,2.25,0.5,14,0.625.
分析:(1)(2)(3)依据四则运算顺序解答,
(4)先运用乘法分配律算出(++)×12=8+5+,再运用加法结合律解答,
(5)设要求的数是x,再依据等式性质解方程求解.
点评:(1)(2)(3)考查学生对于四则运算计算方法掌握,
(4)考察运用乘法分配律以及加法结合律能力,
(5)考查依据等式性质解方程能力.
=2010-505×2.4,
=2010-1212,
=798;
(2)(-×)÷,
=(),
=,
=2.25;
(3)×[-(-)],
=×[-],
=×,
=0.5;
(4)(++)×12+,
=×12×12×12,
=8+5+(),
=13+1,
=14;
(5)设要求的数是x,
18+[×1.25+(+x×12)]÷0.125=86,
18+[×1.25++12x]÷0.125=86,
18+[1+12x]÷0.125=86,
18+8+96x=86,
26+96x-26=86-26,
96x÷96=60÷96,
x=0.625.
答:要求的数是0.625,
故答案为:798,2.25,0.5,14,0.625.
分析:(1)(2)(3)依据四则运算顺序解答,
(4)先运用乘法分配律算出(++)×12=8+5+,再运用加法结合律解答,
(5)设要求的数是x,再依据等式性质解方程求解.
点评:(1)(2)(3)考查学生对于四则运算计算方法掌握,
(4)考察运用乘法分配律以及加法结合律能力,
(5)考查依据等式性质解方程能力.
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