题目内容
(1)0.625×50+0.625×3.46+5.346×3.75;
(2)189
×(2-
)
(2)189
1 |
191 |
189 |
190 |
考点:四则混合运算中的巧算
专题:计算问题(巧算速算)
分析:(1)0.625×50+0.625×3.46+5.346×3.75,转化为:0.625×50+0.625×3.46+32.076×0.625,运用乘法分配律简算.
(2)把189
变为(190-
),算出(2-
)里面的结果,进一步利用乘法分配律简算即可.
(2)把189
1 |
191 |
190 |
191 |
189 |
190 |
解答:
解:(1)0.625×50+0.625×3.46+5.346×3.75;
=0.625×50+0.625×3.46+32.076×0.625
=0.625×(50+3.46+32.076)
=0.625×85.536
=53.46
(2)189
×(2-
)
=(190-
)×
=190×
-
×
=191-1
=190
=0.625×50+0.625×3.46+32.076×0.625
=0.625×(50+3.46+32.076)
=0.625×85.536
=53.46
(2)189
1 |
191 |
189 |
190 |
=(190-
190 |
191 |
191 |
190 |
=190×
191 |
190 |
190 |
191 |
191 |
190 |
=191-1
=190
点评:(1)此题考查的目的是理解掌握乘法分配律的意义,并且能够灵活运用乘法分配律进行简便计算.
(2)利用数字特点,适当变形,进一步利用运算定律简算.
(2)利用数字特点,适当变形,进一步利用运算定律简算.
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