题目内容
简便计算
248+28+52+72 | 53×98 | 44×25 | 27×57+57×73 | 25×32×125 | 96×107. |
解:(1)248+28+52+72,
=(248+52)+(28+72),
=300+100,
=400;
(2)53×98,
=53×(100-2),
=5300-106,
=5194;
(3)44×25,
=11×4×25,
=11×(4×25),
=11×100,
=1100;
(4)27×57+57×73,
=57×(27+73),
=57×100,
=5700;
(5)25×32×125,
=25×4×8×125,
=(25×4)×(8×125),
=100×1000,
=100000;
(6)96×107,
=96×(100+7),
=9600+96×7,
=9600+(100-4)×7,
=9600+700-28,
=10272.
分析:(1)运用加法交换律与结合律简算;
(2)把98看作100-2,运用乘法分配律简算;
(3)把44看作11×4,运用乘法结合律简算;
(4)运用乘法分配律简算;
(5)把32看作4×8,运用乘法结合律简算;
(6)把107看作100+7,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.
=(248+52)+(28+72),
=300+100,
=400;
(2)53×98,
=53×(100-2),
=5300-106,
=5194;
(3)44×25,
=11×4×25,
=11×(4×25),
=11×100,
=1100;
(4)27×57+57×73,
=57×(27+73),
=57×100,
=5700;
(5)25×32×125,
=25×4×8×125,
=(25×4)×(8×125),
=100×1000,
=100000;
(6)96×107,
=96×(100+7),
=9600+96×7,
=9600+(100-4)×7,
=9600+700-28,
=10272.
分析:(1)运用加法交换律与结合律简算;
(2)把98看作100-2,运用乘法分配律简算;
(3)把44看作11×4,运用乘法结合律简算;
(4)运用乘法分配律简算;
(5)把32看作4×8,运用乘法结合律简算;
(6)把107看作100+7,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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