题目内容
(1+
)+(2+
)+(3+
)+…+(97+
).
| 1 |
| 97 |
| 2 |
| 97 |
| 3 |
| 97 |
| 97 |
| 97 |
分析:(1+
)+(2+
)+(3+
)+…+(97+
)还可以写成(1+
)+2×(1+
)+3×(1+
)+…97×(1+
),然后利用分配律变式为(1+2+3…+97)×(1+
)的形式,计算即可解答.
| 1 |
| 97 |
| 2 |
| 97 |
| 3 |
| 97 |
| 97 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
解答:解:(1+
)+(2+
)+(3+
)+…+(97+
)
=(1+
)+2×(1+
)+3×(1+
)+…97×(1+
),
=(1+2+3…+97)×(1+
),
=
×(1+
)
=
×1+
×
=4753+49
=4802
| 1 |
| 97 |
| 2 |
| 97 |
| 3 |
| 97 |
| 97 |
| 97 |
=(1+
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
=(1+2+3…+97)×(1+
| 1 |
| 97 |
=
| 97×(97+1) |
| 2 |
| 1 |
| 97 |
=
| 97×(97+1) |
| 2 |
| 97×(97+1) |
| 2 |
| 1 |
| 97 |
=4753+49
=4802
点评:本题主要考查分数的巧算,熟练利用运算律是解答本题的关键.
练习册系列答案
相关题目