题目内容
脱式计算(能简算的要简算)
9.8×75+75×0.2 | 0.78÷0.25÷40 | 7.2+2.8×5.06 | 56×10.1 |
解:(1)9.8×75+75×0.2,
=(9.8+0.2)×75,
=10×75,
=750;
(2)0.78÷0.25÷40,
=0.78÷(0.25×40),
=0.78÷10,
=7.8;
(3)7.2+2.8×5.06,
=7.2+14.86,
=21.368;
(4)56×10.1,
=56×(10+0.1),
=56×10+5.6×0.1,
=560+0.56,
=560.56.
分析:(1)运用乘法分配律简算;
(2)运用除法的性质简算;
(3)先算乘法,再算加法;
(4)把10.1看作10+0.1,运用乘法分配律简算.
点评:完成本题,要注意分析式中数据,运用合适的简便方法计算.
=(9.8+0.2)×75,
=10×75,
=750;
(2)0.78÷0.25÷40,
=0.78÷(0.25×40),
=0.78÷10,
=7.8;
(3)7.2+2.8×5.06,
=7.2+14.86,
=21.368;
(4)56×10.1,
=56×(10+0.1),
=56×10+5.6×0.1,
=560+0.56,
=560.56.
分析:(1)运用乘法分配律简算;
(2)运用除法的性质简算;
(3)先算乘法,再算加法;
(4)把10.1看作10+0.1,运用乘法分配律简算.
点评:完成本题,要注意分析式中数据,运用合适的简便方法计算.
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