题目内容
计算41
×
+51
×
+61
×
.
| 1 |
| 3 |
| 3 |
| 4 |
| 1 |
| 2 |
| 4 |
| 5 |
| 3 |
| 5 |
| 5 |
| 6 |
考点:分数的巧算
专题:计算问题(巧算速算)
分析:通过观察,每一项两个分数之间的关系,把带分数拆成整十数+假分数形式,每一项运用乘法分配律简算即可.
解答:
解:41
×
+51
×
+61
×
=(40+
)×
+(50+
)×
+(60+
)×
=30+1+40+
+50+
=121+(
+
)
=121+1
=122
| 1 |
| 3 |
| 3 |
| 4 |
| 1 |
| 2 |
| 4 |
| 5 |
| 3 |
| 5 |
| 5 |
| 6 |
=(40+
| 4 |
| 3 |
| 3 |
| 4 |
| 3 |
| 2 |
| 4 |
| 5 |
| 8 |
| 5 |
| 5 |
| 6 |
=30+1+40+
| 6 |
| 5 |
| 3 |
| 4 |
=121+(
| 6 |
| 5 |
| 3 |
| 4 |
=121+1
| 19 |
| 20 |
=122
| 19 |
| 20 |
点评:此题的关键就是将每个式子中的第一个因数进行巧妙拆分,使计算简便.
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