题目内容
下面各题,怎样算简便就怎样算.
| 37×8+63×8 | 44×25 | 45×99 | 99×48+48 |
| (20+4)×25 | 36×127-27×36 | [548-(124+215)]×27. |
考点:整数四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)(3)(4)(5)(6)利用乘法分配律简算;
(2)把44=11×4,利用乘法结合律简算;
(7)先算加法,再算减法,最后算乘法.
(2)把44=11×4,利用乘法结合律简算;
(7)先算加法,再算减法,最后算乘法.
解答:
解:(1)37×8+63×8
=(37+63)×8
=100×8
=800;
(2)44×25
=11×(4×25)
=11×100
=1100;
(3)45×99
=45×100-45×1
=4500-45
=4455;
(4)99×48+48
=(99+1)×48
=100×48
=4800;
(5)(20+4)×25
=20×25+4×25
=500+100
=600;
(6)36×127-27×36
=36×(127-27)
=36×100
=3600;
(7)[548-(124+215)]×27
=[548-339]×27
=209×27
=5643.
=(37+63)×8
=100×8
=800;
(2)44×25
=11×(4×25)
=11×100
=1100;
(3)45×99
=45×100-45×1
=4500-45
=4455;
(4)99×48+48
=(99+1)×48
=100×48
=4800;
(5)(20+4)×25
=20×25+4×25
=500+100
=600;
(6)36×127-27×36
=36×(127-27)
=36×100
=3600;
(7)[548-(124+215)]×27
=[548-339]×27
=209×27
=5643.
点评:整数混合运算的关键是抓住运算顺序,正确利用运算定律简算.
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