题目内容
| 下面各题,怎样简便就怎样计算. 99×43+43 |
25×26×8 | 102×36 |
| 59×299 | 16×5+34×5+28 | 125×44. |
分析:(1)(5)逆用乘法分配律简算;
(2)运用乘法交换律和结合律简算;
(3)(4)运用乘法分配律简算;
(6)运用乘法结合律简算.
(2)运用乘法交换律和结合律简算;
(3)(4)运用乘法分配律简算;
(6)运用乘法结合律简算.
解答:解:(1)99×43+43,
=(99+1)×43,
=4300;
(2)25×26×8,
=(25×8)×26,
=200×26,
=5200;
(3)102×36,
=(100+2)×36,
=3600+72,
=3672;
(4)59×299,
=59×(300-1),
=17700-59,
=17641;
(5)16×5+34×5+28,
=(16+34)×5+28,
=50×5+28,
=250+28,
=278;
(6)125×44,
=125×4×11,
=500×11,
=5500.
=(99+1)×43,
=4300;
(2)25×26×8,
=(25×8)×26,
=200×26,
=5200;
(3)102×36,
=(100+2)×36,
=3600+72,
=3672;
(4)59×299,
=59×(300-1),
=17700-59,
=17641;
(5)16×5+34×5+28,
=(16+34)×5+28,
=50×5+28,
=250+28,
=278;
(6)125×44,
=125×4×11,
=500×11,
=5500.
点评:此题主要考查应用运算定律进行简便计算,关键是根据数据和符号的特点,灵活选用运算定律,从而简算得解..
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