题目内容
怎样简便就怎样算. 88×0.25×9 | 1.2×9.7+0.3×1.2 | 5.64÷0.4+0.6×1.8 | (12.5+0.125)×8. |
解:
(1)88×0.25×9,
=(8×11)×0.25×9,
=(8×0.25)×(11×9),
=2×99,
=198;
(2)1.2×9.7+0.3×1.2,
=1.2×(9.7+0.3),
=1.2×10,
=12;
(3)5.64÷0.4+0.6×1.8,
=14.1+1.08,
=15.18;
(4)(12.5+0.125)×8,
=12.5×8+0.125×8,
=100+1,
=101.
分析:(1)根据乘法交换律和结合律进行简算;
(2)根据乘法分配律进行简算;
(3)先算除法和乘法,再算加法;
(4)根据乘法分配律进行简算.
点评:此题主要考查小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
(1)88×0.25×9,
=(8×11)×0.25×9,
=(8×0.25)×(11×9),
=2×99,
=198;
(2)1.2×9.7+0.3×1.2,
=1.2×(9.7+0.3),
=1.2×10,
=12;
(3)5.64÷0.4+0.6×1.8,
=14.1+1.08,
=15.18;
(4)(12.5+0.125)×8,
=12.5×8+0.125×8,
=100+1,
=101.
分析:(1)根据乘法交换律和结合律进行简算;
(2)根据乘法分配律进行简算;
(3)先算除法和乘法,再算加法;
(4)根据乘法分配律进行简算.
点评:此题主要考查小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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