题目内容
简便计算.
101×78 | 25×88 | 99×76+76 |
5×38×4×5 | (25+20)×4 | 35×103-3×35. |
解:
(1)101×78,
=(100+1)×78,
=100×78+78,
=7800+78,
=7878;
(2)25×88,
=25×(4×22),
=(25×4)×22,
=100×22,
=2200;
(3)99×76+76,
=(99+1)×76,
=100×76,
=7600;
(4)5×38×4×5,
=(5×5×4)×38,
=100×38,
=3800;
(5)(25+20)×4,
=25×4+20×4,
=100+80,
=180;
(6)35×103-3×35,
=(103-3)×35,
=100×35,
=3500.
分析:(1)根据乘法分配律进行计算;
(2)根据乘法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法交换律和结合律进行计算;
(5)根据乘法分配律进行计算;
(6)根据乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
(1)101×78,
=(100+1)×78,
=100×78+78,
=7800+78,
=7878;
(2)25×88,
=25×(4×22),
=(25×4)×22,
=100×22,
=2200;
(3)99×76+76,
=(99+1)×76,
=100×76,
=7600;
(4)5×38×4×5,
=(5×5×4)×38,
=100×38,
=3800;
(5)(25+20)×4,
=25×4+20×4,
=100+80,
=180;
(6)35×103-3×35,
=(103-3)×35,
=100×35,
=3500.
分析:(1)根据乘法分配律进行计算;
(2)根据乘法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法交换律和结合律进行计算;
(5)根据乘法分配律进行计算;
(6)根据乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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